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Tác giả Chủ đề: Một số vấn đề về hóa học Hữu Cơ  (Đọc 60929 lần)

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sonquan1421988

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Re: C17H17NO5
« Trả lời #165 vào lúc: Tháng Hai 12, 2011, 07:28:18 PM »
Nordidemnin, Didemnin B, NorD, NSC-325319

Activation of Boc-allo-isoleucine acid (I) with CDI in THF followed by reaction with ethyl lithioacetate (II) in THF, affords beta-keto ester (III) (alternatively, (III) can be obtained as follows: formation of the corresponding methyl ester of (I) by reaction with MeI and KHCO3 in DMF, followed by reduction with NaBH4 and LiCl in THF/EtOH and subsequent Swern oxidation with pyr:SO3, Et3N and DMSO provides aldehyde (IV), which is then condensed to ethyl lithioacetate (II) in THF and finally oxidized with PDC in CH2Cl2/HOAc). Stereospecific reduction of beta-keto ester (III) with NaBH4 in EtOH affords beta-hydroxy ester (V) (1-3), which is first saponified with NaOH in EtOH and then esterified with trichloroethanol (VI) by means of DCC and DMAP in CH2Cl2, furnishing ester (VII). Removal of the Boc group of (VII) by means of HCl/dioxane yields amine derivative (VIII), which is then coupled to Boc-Thr(Bzl)-OH (IX) by means of diethyl phosphorocyanidate (DEPC) and DIEA in DMF and treated with HCl for Boc removal, allowing isolation of dipeptide (X). Coupling of (X) with Boc-MeLeu-OH (XI) -- obtained in turn by methylation of Boc-Leu-OH (XII) with MeI and NaH in THF -- with DEPC and Et3N in DMF, followed by O-protection with TBDMSCl and imidazole in DMF, provides tripeptide (XIII). Removal of the benzyl group of (XIII) by hydrogenation over Pd/C in THF affords Boc-Me-Leu-Thr-Ist(TBDMS)-OTce (XIV), which is then coupled with Z-Me-Tyr(Me)-OH (XV) by means of DMAP and DCC in CH2Cl2 to furnish depsipeptide (XVII) (protected amino acid Z-Me-Tyr(Me)-OH (XV) can be obtained in turn by methylation of Z-Tyr-OH (XVI) with MeI and NaH in THF). Deprotection of (XVII) by first treatment with Zn in THF in the presence of NH4OAc yields fragment (XVIII).
Hamada, Y.; et al.; Efficient total synthesis of didemnins A and B. J Am Chem Soc 1989, 111, 2, 669
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Nordidemnin, Didemnin B, NorD, NSC-325319

Activation of Boc-allo-isoleucine acid (I) with CDI in THF followed by reaction with ethyl lithioacetate (II) in THF, affords beta-keto ester (III) (alternatively, (III) can be obtained as follows: formation of the corresponding methyl ester of (I) by reaction with MeI and KHCO3 in DMF, followed by reduction with NaBH4 and LiCl in THF/EtOH and subsequent Swern oxidation with pyr:SO3, Et3N and DMSO provides aldehyde (IV), which is then condensed to ethyl lithioacetate (II) in THF and finally oxidized with PDC in CH2Cl2/HOAc). Stereospecific reduction of beta-keto ester (III) with NaBH4 in EtOH affords beta-hydroxy ester (V) (1-3), which is first saponified with NaOH in EtOH and then esterified with trichloroethanol (VI) by means of DCC and DMAP in CH2Cl2, furnishing ester (VII). Removal of the Boc group of (VII) by means of HCl/dioxane yields amine derivative (VIII), which is then coupled to Boc-Thr(Bzl)-OH (IX) by means of diethyl phosphorocyanidate (DEPC) and DIEA in DMF and treated with HCl for Boc removal, allowing isolation of dipeptide (X). Coupling of (X) with Boc-MeLeu-OH (XI) -- obtained in turn by methylation of Boc-Leu-OH (XII) with MeI and NaH in THF -- with DEPC and Et3N in DMF, followed by O-protection with TBDMSCl and imidazole in DMF, provides tripeptide (XIII). Removal of the benzyl group of (XIII) by hydrogenation over Pd/C in THF affords Boc-Me-Leu-Thr-Ist(TBDMS)-OTce (XIV), which is then coupled with Z-Me-Tyr(Me)-OH (XV) by means of DMAP and DCC in CH2Cl2 to furnish depsipeptide (XVII) (protected amino acid Z-Me-Tyr(Me)-OH (XV) can be obtained in turn by methylation of Z-Tyr-OH (XVI) with MeI and NaH in THF). Deprotection of (XVII) by first treatment with Zn in THF in the presence of NH4OAc yields fragment (XVIII).
Harris, B.D.; et al.; Synthetic studies of didemnins. II. Approaches to statine diastereomers. Tetrahedron Lett 1987, 28, 25, 2837
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Nordidemnin, Didemnin B, NorD, NSC-325319

Activation of Boc-allo-isoleucine acid (I) with CDI in THF followed by reaction with ethyl lithioacetate (II) in THF, affords beta-keto ester (III) (alternatively, (III) can be obtained as follows: formation of the corresponding methyl ester of (I) by reaction with MeI and KHCO3 in DMF, followed by reduction with NaBH4 and LiCl in THF/EtOH and subsequent Swern oxidation with pyr:SO3, Et3N and DMSO provides aldehyde (IV), which is then condensed to ethyl lithioacetate (II) in THF and finally oxidized with PDC in CH2Cl2/HOAc). Stereospecific reduction of beta-keto ester (III) with NaBH4 in EtOH affords beta-hydroxy ester (V) (1-3), which is first saponified with NaOH in EtOH and then esterified with trichloroethanol (VI) by means of DCC and DMAP in CH2Cl2, furnishing ester (VII). Removal of the Boc group of (VII) by means of HCl/dioxane yields amine derivative (VIII), which is then coupled to Boc-Thr(Bzl)-OH (IX) by means of diethyl phosphorocyanidate (DEPC) and DIEA in DMF and treated with HCl for Boc removal, allowing isolation of dipeptide (X). Coupling of (X) with Boc-MeLeu-OH (XI) -- obtained in turn by methylation of Boc-Leu-OH (XII) with MeI and NaH in THF -- with DEPC and Et3N in DMF, followed by O-protection with TBDMSCl and imidazole in DMF, provides tripeptide (XIII). Removal of the benzyl group of (XIII) by hydrogenation over Pd/C in THF affords Boc-Me-Leu-Thr-Ist(TBDMS)-OTce (XIV), which is then coupled with Z-Me-Tyr(Me)-OH (XV) by means of DMAP and DCC in CH2Cl2 to furnish depsipeptide (XVII) (protected amino acid Z-Me-Tyr(Me)-OH (XV) can be obtained in turn by methylation of Z-Tyr-OH (XVI) with MeI and NaH in THF). Deprotection of (XVII) by first treatment with Zn in THF in the presence of NH4OAc yields fragment (XVIII).
Hamada, Y.; Shioiri, T.; Anti-tumor active cyclic peptide derived from marine organism: Synthesis, conformation and bioactivity. Kagaku Zokan 1990, 118, 31
**********
Tirofiban hydrochloride, MK-383, L-700462, Aggrastat

4-Pyridineacetic acid (I) was hydrogenated to the corresponding piperidine (II) in the presence of PtO2. After protection of (II) as the N-Boc derivative (III), reduction of its carboxylate group with borane in THF provided alcohol (IV). Subsequent Swern oxidation of alcohol (IV) furnished aldehyde (V). This was then subjected to a Wittig condensation with carbomethoxytriphenylphosphorane to yield the unsaturated ester (VI), which was further hydrogenated to (VII) in the presence of Pd/C. After saponification of the methyl ester function of (VII), the resultant carboxylic acid was reduced to alcohol (VIII) by means of borane in THF. Conversion of alcohol (VIII) into the alkyl bromide (IX) was accomplished by treatment with carbon tetrabromide and triphenylphosphine. Then, alkylation of the phenolic hydroxyl of N-Cbz-L-tyrosine (X) with bromide (IX) in the presence of NaH in DMF afforded adduct (XI).
Egbertson, M.S.; Chang, C.T.C.; Duggan, M.E.; et al.; Non-peptide fibrinogen receptor antagonists. 2. Optimization of a tyrosine template as a mimic for Arg-Gly-Asp. J Med Chem 1994, 37, 16, 2537
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Tirofiban hydrochloride, MK-383, L-700462, Aggrastat

4-Pyridineacetic acid (I) was hydrogenated to the corresponding piperidine (II) in the presence of PtO2. After protection of (II) as the N-Boc derivative (III), reduction of its carboxylate group with borane in THF provided alcohol (IV). Subsequent Swern oxidation of alcohol (IV) furnished aldehyde (V). This was then subjected to a Wittig condensation with carbomethoxytriphenylphosphorane to yield the unsaturated ester (VI), which was further hydrogenated to (VII) in the presence of Pd/C. After saponification of the methyl ester function of (VII), the resultant carboxylic acid was reduced to alcohol (VIII) by means of borane in THF. Conversion of alcohol (VIII) into the alkyl bromide (IX) was accomplished by treatment with carbon tetrabromide and triphenylphosphine. Then, alkylation of the phenolic hydroxyl of N-Cbz-L-tyrosine (X) with bromide (IX) in the presence of NaH in DMF afforded adduct (XI).
Egbertson, M.S.; Laswell, W.L.; Hartman, G.D.; Duggan, M.E.; Halczenko, W. (Merck & Co., Inc.); Novel sulfonamide fibrinogen receptor antagonists. EP 0478363; EP 0743302; JP 1992288051; US 5292756
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Tirofiban hydrochloride, MK-383, L-700462, Aggrastat

4-Pyridineacetic acid (I) was hydrogenated to the corresponding piperidine (II) in the presence of PtO2. After protection of (II) as the N-Boc derivative (III), reduction of its carboxylate group with borane in THF provided alcohol (IV). Subsequent Swern oxidation of alcohol (IV) furnished aldehyde (V). This was then subjected to a Wittig condensation with carbomethoxytriphenylphosphorane to yield the unsaturated ester (VI), which was further hydrogenated to (VII) in the presence of Pd/C. After saponification of the methyl ester function of (VII), the resultant carboxylic acid was reduced to alcohol (VIII) by means of borane in THF. Conversion of alcohol (VIII) into the alkyl bromide (IX) was accomplished by treatment with carbon tetrabromide and triphenylphosphine. Then, alkylation of the phenolic hydroxyl of N-Cbz-L-tyrosine (X) with bromide (IX) in the presence of NaH in DMF afforded adduct (XI).
Egbertson, M.S.; Hartman, G.D.; Halczenko, W.; Laswell, W.L.; Duggan, M.E. (Merck & Co., Inc.); Novel sulfonamide fibrinogen receptor antagonists. WO 9319046
*************
Dehydrodidemnin B, Aplidine, DDB, Aplidin

The modified tyrosine building block (II) was prepared by alkylation of N-Cbz-L-tyrosine (I) at both the phenolic OH and the NH groups employing dimethyl sulfate under phase-transfer conditions. N-Boc-L-Threonine benzyl ether (III) was converted to the corresponding (triethylsilyl)ethoxymethyl ester, and the O-benzyl group was subsequently removed by catalytic hydrogenolysis to afford (IV). Coupling between the tyrosine (II) and threonine (IV) derivatives using DCC and DMAP gave rise to the protected didepsipeptide (V). The SEM protecting group was then cleaved by means of HF in acetonitrile, yielding intermediate (VI)
ou, G.; Gonz醠ez, I.; Albericio, F.; Lloyd-Williams, P.; Giralt, E.; Total synthesis of dehydrodidemnin B. Use of uronium and phosphonium salt coupling reagents in peptide synthesis in solution. J Org Chem 1997, 62, 2, 354
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Dehydrodidemnin B, Aplidine, DDB, Aplidin

he modified tyrosine building block (II) was prepared by alkylation of N-Cbz-L-tyrosine (I) at both the phenolic OH and the NH groups employing dimethyl sulfate under phase-transfer conditions. N-Boc-L-Threonine benzyl ether (III) was converted to the corresponding (triethylsilyl)ethoxymethyl ester, and the O-benzyl group was subsequently removed by catalytic hydrogenolysis to afford (IV). Coupling between the tyrosine (II) and threonine (IV) derivatives using DCC and DMAP gave rise to the protected didepsipeptide (V). The SEM protecting group was then cleaved by means of HF in acetonitrile, yielding intermediate (VI)
Giralt Lledo, E.; Albericio Palomera, F.; Lloyd-Williams, P.; Gonz醠ez Valc醨cel, I.; Jou Prat, G.; G髆ez Gonz醠ez, A.; Manzanares Secades, I. (PharmaMar, SA); Process for the preparation of didemnine A. ES 2102322
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Frakefamide, SPD-759, LEF-576, BCH-3963

N-Cbz-D-Alanine (VIII) is activated as the mixed anhydride (IX) and subsequently coupled to the dipeptide amide (VII), producing (X). Deprotection of the N-Cbz group of tripeptide (X) by hydrogenolysis over Pd/C yields (XI). The mixed anhydride (XIII) (prepared from N-Cbz-L-tyrosine (XII) and isobutyl chloroformate) is then coupled to tripeptide (XI), producing (XIV). Finally, removal of the N-Cbz group of (XIV) by catalytic hydrogenolysis furnishes the title compound.
Franz閚, H. (AstraZeneca plc); Process for the preparation of a tetrapeptide. WO 9947548
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Frakefamide, SPD-759, LEF-576, BCH-3963

In an alternative procedure, N-Cbz-L-tyrosine (I) is condensed with D-alanine methyl ester (II), either employing TBTU as the coupling reagent or via previous activation as the mixed anhydride with isobutyl chloroformate, to produce dipeptide (III). After alkaline hydrolysis of the methyl ester function of (III), the resultant carboxylic acid (IV) is coupled to dipeptide amide (V) yielding the protected tetrapeptide (VI). Finally, deprotection of (VI) is carried out by catalytic hydrogenolysis over Pd/C.
Franz閚, H.M.; Bessidskaia, G.; Abedi, V.; Nilsson, A.; Nilsson, M.; Olsson, L.; Frakefamide, an analgesic tetrapeptide: Development of a pilot-plant-scale process. Org Process Res Dev 2002, 6, 6, 788
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Frakefamide, SPD-759, LEF-576, BCH-3963

n an alternative procedure, N-Cbz-L-tyrosine (I) is condensed with D-alanine methyl ester (II), either employing TBTU as the coupling reagent or via previous activation as the mixed anhydride with isobutyl chloroformate, to produce dipeptide (III). After alkaline hydrolysis of the methyl ester function of (III), the resultant carboxylic acid (IV) is coupled to dipeptide amide (V) yielding the protected tetrapeptide (VI). Finally, deprotection of (VI) is carried out by catalytic hydrogenolysis over Pd/C.
Nilsson, M.; Ellburg, M.; Franz鑞, H. (AstraZeneca AB); A process for the preparation of H-Tyr-D-Ala-Phe(F)-Phe-NH2. EP 1212350; JP 2003509437; WO 0119849
************
PNU-177496

Coupling of N-Cbz-tyrosine (I) with n-pentylamine (II) afforded amide (III). Subsequent alkylation of the phenol group of (III) with diethyl chloromalonate (IV) gave phenoxy malonate (V). Hydrogenolytical deprotection of the N-Cbz group of (V) provided the corresponding amine, which was isolated as the hydrochloride salt (VI). Conversion of (VI) to isocyanate (VII) was effected by treatment with diphosgene in the presence of Proton Sponge(r). Addition of phenylalanine ethyl ester (VIII) to isocyanate (VII) furnished urea (IX). Finally, the ethyl ester groups of (IX) were saponified with LiOH to yield the title compound.
Bleasdale, J.; May, P.D.; Schostarez, H.J.; Barf, T.; Larsen, S.D.; Liljebris, C. (Pharmacia Corp.); Inhibitors of protein tyrosine phosphatase. WO 9911606

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Re: C17H17NO5
« Trả lời #165 vào lúc: Tháng Hai 12, 2011, 07:28:18 PM »

Offline solebag

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Re: C17H17NO5
« Trả lời #166 vào lúc: Tháng Hai 14, 2011, 03:00:13 PM »
cam on ban quan nhiu lam. zay cho mih hoi them chut, zay lam de bao quan chat nay(aminoaxit) khi cho no tac dung voi nuoc(H20)?

Offline Duonglt02031992

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1 câu hỏi về Carbon
« Trả lời #167 vào lúc: Tháng Ba 19, 2011, 07:29:54 AM »
Mong mọi người trên diễn đàn giúp mình giải thích:

Vì sao Carbon là nguyên tố duy nhất có thể tạo thành những mạch dài hàng trăm nguyên tử???

Cảm ơn mọi người trước! :'(

Offline toan_bn

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Cho em hỏi về Rodamine B
« Trả lời #168 vào lúc: Tháng Sáu 17, 2011, 11:20:13 AM »
Rodamine B là gì hả các bác? công thức của nó thế nào ạ? em search trên mạng mà ko thấy có. hic. giúp em  với.
Bác nào biết thông tin gửi vào email cho e nhé: nguyenthitoan_bn@yahoo.com
Thanks các bác!
« Sửa lần cuối: Tháng Sáu 17, 2011, 11:33:26 AM gửi bởi toan_bn »

Offline Kr_Chemboy

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Re: Cho em hỏi về Rodamine B
« Trả lời #169 vào lúc: Tháng Sáu 17, 2011, 12:36:47 PM »
Bạn xem ở đây nhé : http://en.wikipedia.org/wiki/Rhodamine_B

Offline Keneory

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Re: Một số vấn đề về hóa học Hữu Cơ
« Trả lời #170 vào lúc: Tháng Bảy 11, 2011, 10:06:43 PM »
Mọi người xem mấy bài này giùm tôi với:
       1. Một axit hữu cơ A: CTPT C5H8O2, có 2 đồng phân hình học. Hiđrô hóa axit hữu cơ đó thu được hợp chất B là C5H10O2, có thể tách B thành 2 đối quang của nhau.
a, Viết CTCT 2 đồng phân hình học của A?
b, Cho mỗi đồng phân của A tác dụng với Brôm. Hãy viết CT Fisơ, CT phối cảnh của sản phẩm sinh ra trong mỗi trường hợp?
c, Nêu 1 pphh tổng hợp chất B từ dẫn xuất Halogen và các hóa chất cần thiết?
       2.Sắp xếp theo chiều tăng dần tính axit của các chất sau:
Axit axetic; axit 2,2 đi metyl propanoic; phenol; ancol etylic; para metyl phenol; ancol iso propylic; para nitro phenol; ancol tert butylic.
       3. Xác định các chất chưa biết. Viết PTPƯ bằng CTCT ( các chất phản ứng tỷ lệ 1:1, các chất trong sơ đồ là sản phẩm chính)
n-propyl benzen -> ( đk: Br2, Fe, t0) A -> (đk: H2O, KOH, t0, P cao) B -> ( đk: CH3COCl, KOH) C
n- propyl benzen -> (đk: Br2, as, t0) D -> ( đk: C2H5OH, KOH) E -> ( Br2, dmpc) F -> ( KOH, H2O) G <- ( đk1: C2H5MgBr; đk2: H2O) H
LIKE THE STORM, AS THE FLOOD, THOUGH THE DARK, UPON THE LIGHT...!!!

Offline rjkun

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Phương trình điều chế axit lạctic
« Trả lời #171 vào lúc: Tháng Chín 11, 2011, 11:17:27 AM »
Các bác ơi cho e hỏi , chất Y mà điều chế ra X chỉ wa 1 pt là có phải axit lactic điều chế từ axit formic hôn .
Nếu k phải thì cho hỏi x,y có thể là chất nào ^^ thanks !! c017

Offline tu_dido

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Re: Một số vấn đề về hóa học Hữu Cơ
« Trả lời #172 vào lúc: Tháng Chín 30, 2011, 10:57:24 PM »
ai có tài liệu về phức xelat trong các dung môi hữu cơ ,tách chiết các xelat đưa lên hay gửi mình  vutu1612@gmail.com thanks nhiu!

Offline hona2707

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cần xin tài liệu về ankan
« Trả lời #173 vào lúc: Tháng Mười Hai 12, 2011, 09:20:58 PM »
tình hình là em phải làm 1 bài để nộp vào thứ 7 này em cần tìm clip hoặc flash về
1./ phản ứng thế của ankan
2./ cơ chế phản ứng thế
Anh Chị hoặc Thầy Cô nào có cho em xin với
mọi người có thể comment trực tiếp tại topic hoặc gởi về mail : tranhoangnam2707@yahoo.com.vn
Xin chân thành cảm ơn

Offline nhutrang3788

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Re: cần xin tài liệu về ankan
« Trả lời #174 vào lúc: Tháng Hai 03, 2012, 04:19:07 PM »
Bạn tìm sách: Hóa học hữu cơ của PGS.TS Nguyễn Hữu Đĩnh và PSG.TS Đỗ Đình Rãng về đọc nha.
Gook luck!

Offline chemistry2810

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Re: Một số vấn đề về hóa học Hữu Cơ
« Trả lời #175 vào lúc: Tháng Tư 12, 2012, 09:20:47 PM »
ai có tài liệu về phức xelat trong các dung môi hữu cơ ,tách chiết các xelat đưa lên hay gửi mình  vutu1612@gmail.com thanks nhiu!

Nếu bạn thường xuyên dùng máy tính thì tìm trên google cũng không khó đâu. tìm hộ bạn cái này,
http://d3.violet.vn/uploads/previews/608/2411053/preview.swf

Offline Anhtraj

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[Hỏi] Danh pháp amin vừa bậc 1 vừa bậc 2
« Trả lời #176 vào lúc: Tháng Năm 27, 2012, 09:19:15 PM »
Các bạn cho mình hỏi cách đọc những amin loại có cả bậc 1 và bậc 2,3 kiểu như:
C-N- C-C(CH3)-C-C-C-N-(CH3)2
mình xin cảm ơn
Tạo lập 1 tình yêu với Hóa Học :)

Offline Anhtraj

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Re: [Hỏi] Danh pháp amin vừa bậc 1 vừa bậc 2
« Trả lời #177 vào lúc: Tháng Năm 27, 2012, 09:49:51 PM »
có bạn nào giúp m hem??
Tạo lập 1 tình yêu với Hóa Học :)

Offline abcnguyen

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Cho em hỏi tý
« Trả lời #178 vào lúc: Tháng Chín 28, 2012, 11:02:03 PM »
Ai biết áp suất hơi bão hào của Butan ở 25 độ C không chỉ em với? Hic

Offline noibinhyenchimhot

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So sánh tính acid giữa acid chloroacetic và acid glycolic (acid hydroxyacetic) !
« Trả lời #179 vào lúc: Tháng Mười Một 12, 2012, 02:17:36 PM »
Xin chào mọi người,

Cho NBYCH hỏi giữa hai acid trên thì chất nào có tính acid mạnh hơn ? Giải thích tại sao ?
Cám ơn các anh, chị rất nhiều.


NBYCH

 

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