- A simple synthesis of polyfunctionalized 4-aminopyrazolidin-3-ones as 'aza-deoxa' analogs of D-cycloserine
-
A simple five-step synthesis of fully substituted (4RS,5RS)-4- aminopyrazolidin-3-ones as analogs of D-cycloserine was developed. It comprises a two-step preparation of 5-substituted (4RS,5RS)-4-(benzyloxycarbonylamino) pyrazolidin-3-ones, reductive alkyl
- Novak, Ana,Stefanic, Matej,Groselj, Uros,Hrast, Martina,Kasunic, Marta,Gobec, Stanislav,Stanovnik, Branko,Svete, Jurij
-
p. 245 - 267
(2014/03/21)
-
- Amino Acids, 18. - Preparation and Reactions of 2-Isocyanato-2-alkenoates
-
2-Isocyanato-2-alkenoates 3 were obtained in good yields by the perrhenate-catalyzed decomposition of 2-azidoalkanoates 1 in the presence of diphosgene (2a) or phosgene (2b).Methyl 2-azidopropionate (1h) reacts to give a mixture of methyl 2-isocyanato-2-p
- Effenberger, Franz,Kuehlwein, Juergen,Baumgartner, Christian
-
p. 1069 - 1074
(2007/10/02)
-
- Amino Acids, 16. - Synthesis of N-Acyl-2,3-didehydro-2-amino Acid Esters
-
N-Acyl-2,3-didehydro-2-amino acid esters 3, 5, 7-12, with a great variety of N-substituents, are obtained in good yields by the perrhenate-catalyzed decomposition of methyl 2-azido carboxylates 1 in organic solvents in the presence of the corresponding acyl chlorides 2.By using methyl 2-azido-isovalerate (1a), the conditions (catalyst, solvent, temperature) for the reaction to give 3a were optimized.The reactivity of acyl chlorides can be strongly enhanced with equimolar amounts of dimethyl formamide, which allows a lowering of the decomposition temperature for this reaction.Under these mild reaction conditions also the unstable N-acyldehydroalanine derivative 5f can be obtained in good yield. - Key Words: 2-Azidocarboxylates/ Rhenium catalysts/ Amino acids
- Effenberger, Franz,Kuehlwein, Juergen,Drauz, Karlheinz
-
p. 1295 - 1302
(2007/10/02)
-
- Diastereoselective formation of (Z)-didehydroamino acid esters
-
The rearrangement of (E)-didehydroamino acid derivatives to the corresponding Z-derivatives under acid or basic catalysis as well as under the influence of radicals has been investigated. The condensation of N-benzyloxycarbonyl or N-tert-butoxycarbonyl protected alkyl 2-amino-2-(dimethoxyphosphoryl)acetates with aldehydes or ketones in dichloromethane in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene furnishes (Z)-didehydroamino acid ester derivatives diastereoselectively in excellent yields and with high purity.
- Schmidt,Griesser,Leitenberger,Lieberknecht,Mangold,Meyer,Riedl
-
p. 487 - 490
(2007/10/02)
-
- N-Acyl Dehydro-α-amino Acids from N-Formyl Dehydro-α-amino Acid Esters
-
On treatment with methyl potassioisocyanoacetate (2), aldehydes and ketones 1 give N-anionized N-formyl dehydro-α-amino acid methyl esters 3.Compounds 3 with R1 = CH3, R2 = H is obtained by base induced ring opening of methyl 2-oxazoline-4-carboxylate 5. - Acylation of 3, followed by deformation of the intermediates 6, yields N-acyl dehydro α-amino acid methyl esters 7 which can be hydrolyzed to the N-acyl dehydro α-amino-acids 8.
- Schoellkopf, Ulrich,Meyer, Rolf
-
p. 1469 - 1475
(2007/10/02)
-