Unsubstituted aminosugars readily react with dithiocarboxylic ester or O-ethyl thioformate to yield the hitherto unknown free N-thioacylated sugars which are of biological interest.
Photocycloaddition reactions of the first stable thioaldehyde: 2,4,6-tri(tert-butyl)thiobenzaldehyde with substituted allenes
作者:G. Hofstra、J. Kamphuis、H.J.T. Bos
DOI:10.1016/s0040-4039(01)80050-2
日期:1984.1
Irradiation of 2,4,6-tri-(tert,-butyl)thiobenzaldehyde 1 with some alkoxy-, alkylthio-, and phenyl-allenes 2 a-i gave one stereoisomer of a (2+2)-cycloadduct, viz. thietane 3 in high yields (75–95%). Ringclosure is in agreement with MNDO-calculations.
Synthese a partir de la neopentylthio-2 acetophenone. Reactivite de ce thioaldehyde vis-a-vis de phenyl-lithium, butyl-lithium, acide chloro-3 perbenzoique, et (phenyl-3 propylidene triphenyl) phosphorane
合成 a partir de la neopentylthio-2 acetophenone。Reactive de ce thioaldehyde vis-a-vis-a-vis de phenyl-lithium, 丁基-lithium, acide chloro-3 perbenzoique, et (phenyl-3 亚丙基三苯基) 正膦
3-Trifluoromethylcephalosporins. I. Total synthesis of tert-butyl (.+-.)-7-amino-3-trifluoromethyl-3-cephem-4-carboxylate.
tert-Butyl (±)-7-amino-3-trifluoromethyl-3-cephem-4-carboxylate (16) and the 2-cephem derivative (21) were obtained by total synthesis starting from tert-butyl N-benzylideneglycinate (1). This synthesis is the first example of the reaction of the N-benzylideneglycinate anion with a reactive α-haloketone to give a β-hydroxy-γ-halo-α-aminoester (5a and 5b). The amino esters were treated with ethyl thioformate and then potassium carbonate, leading to the 4, 5-dihydro-6H-1, 3-thiazine derivatives (8a and 8b). After cycloaddition of 8a and 8b with azidoacetyl chloride and catalytic hydrogenation of the azido group, the resulting trans 7-aminocephem compound (12) was converted to the cis isomer (16) by the established method, involving reduction of the o-nitrobenzenesul-fenimino derivative (14).
One-Pot Synthesis of 4-Substituted 3-Amino-2-cyanothiophenes Involving <i>O</i>-Ethyl Thioformate
作者:Haiming Zhang、Mark S. Bednarz、Ngiap-Kie Lim、Gonzalo Hernandez、Wenxue Wu
DOI:10.1021/ol500895t
日期:2014.5.2
An efficient one-pot synthesis of 4-substituted 3-amino-2-cyanothiophenes is described. Treatment of 2-alkyl or aryl substituted acetonitrile sequentially with 2.1 equiv of LDA, 1.1 equiv of O-ethyl thioformate, and 1.2 equiv of 2-chloroacetonitrile afforded the thiophenes in moderate to good yields. The thiophene core can be readily incorporated into more elaborate pharmaceutically relevant structures
描述了4-取代的3-氨基-2-氰基噻吩的有效的一锅合成。依次用2.1当量的LDA,1.1当量的O-乙基硫代甲酸酯和1.2当量的2-氯乙腈处理2-烷基或芳基取代的乙腈,以中等至良好的产率得到噻吩。噻吩核心可以很容易地并入更精细的药学相关结构,如仅需两个步骤即可将3-氨基-2-氰基-4-苯基噻吩(1g)转化为各种官能化的噻吩并[3,2- d ]嘧啶类化合物。