Excess enthalpies of ketone+methyl methylthiomethyl sulfoxide or +dimethyl sulfoxide at 298.15 k

Excess enthalpies of sixteen binary mixtures between one each of methyl methylthiomethyl sulfoxide (MMTSO) and dimethyl sulfoxide (DMSO) and one of ketone {CH₃CO(CH₂)_nCH₃, n=0 to 6 and CH₃COC₆H₅} have been determined at 298.15 K. All the mixtures showed positive excess enthalpies over the whole range of mole fractions. Excess enthalpies of ketone+MMTSO or DMSO increased with increasing the number of methylene radicals in the methyl alkyl ketone molecules. Excess enthalpies of MMTSO+ketone are smaller than those of DMSO+ketone for the same ketone mixtures. The limiting excess partial molar enthalpies of the ketone, H ₁ ^E,∞, in all the mixtures with MMTSO were smaller than those of DMSO. Linear relationships were obtained between limiting excess partial molar enthalpies and the number of methylene groups except 2-propanone.     

A convenient method for the synthesis of cationic glycerolipids with potential biological activity

Cationic ether lipids containing nitrogenous heterocyclic bases as the positively charged groups were synthesized. Treatment of methylthiomethyl ethers of dialkylglycerols with bromine afforded highly reactive -bromo ethers. These products reacted with various nucleophilic reagents giving rise to a series of cationic alkylglycerols.     

Excess enthalpies of alkane-1-amines {CnH2n+1NH2, n = 3-8} + methyl methylthiomethyl sulfoxide and +dimethyl sulfoxide at 298.15 K

Excess enthalpies of binary mixtures between each of alkane-1-amines {C_nH_2n+1NH₂, n=3-8} and methyl methylthiomethyl sulfoxide (MMTSO) or dimethyl sulfoxide (DMSO) have been determined at 298.15 K. All mixtures showed positive enthalpy changes over the whole range of mole fractions.The limiting excess partial molar enthalpies of the aliphatic amines, H₁^E,∞, of all the mixtures with MMTSO or DMSO studied were smaller than those of MMTSO or DMSO, H₂^E,∞, respectively. Linear relations are obtained between limiting excess partial molar enthalpies and number of methylene groups.     

Efficient Synthesis of 3-R-Boc-amino-4-(2,4,5-trifluorophenyl)butyric Acid

3-R-Boc-amino-4-(2,4,5-trifluorophenyl)butyric acid (9) was obtained from L-methionine in six steps with a total yield of 32%. The α-amino acid segment of L-methionine was transferred to chiral aziridine by amino protection, reduction, hydroxyl derivation, and cyclization. After ring opening of 2,4,5-trifluoro-phenyl magnesium bromide, the methylthiomethyl group was then hydrolyzed to β-amino alcohol and oxidized to the target β-amino acid.     

双消除法一锅合成甲硫芳炔化合物

描述了一种方便的合成甲硫芳炔化合物的新方法. 利用亲核硫试剂甲硫甲基苯基砜(methylthiomethyl phenyl sulfone, MP-S)与芳香醛的“一锅反应”, 成功地合成了一系列甲硫芳炔化合物1a～1h．通过对各阶段形成的中间体的分析, 探讨了1的形成机制．实验结果表明, 一锅反应经历了双离去基中间体2的形成和后续的两次消除过程．该方法原料易得, 操作简单, 可得到较好的产率(＞70%). 此外, 反应还具有副产物少、容易分离和纯化的优点．