自称表現に見られる日中両言語の人称代名詞と親族語彙

千葉大学社会文化科学研究科研究プロジェクト報告書第84集『日中両言語における代名詞及び親族語彙の対照研究-琉球方言との比較研究も含めて』所

Microwave-Assisted Improved Synthesis of Oxazolidin-2-ones, Oxazolidine-2-thiones and Thiazolidine-2-thione Chiral Auxiliaries

A microwave assisted method for the synthesis of some typical 4-substituted oxazolidinone chiral auxiliaries used in asymmetric synthesis is reported in this work. Under these conditions, treatment of (S)-phenylalaninol, (S)-phenylglycinol, (S)-valinol and (1S, 2R)-norephedrine with ethyl carbonate or carbon disulfide under the appropriate and specific microwave reaction conditions, led to an efficient synthesis of some oxazolidin-2-ones, oxazolidine-2-thiones and thiazolidine-2-thiones. The methodology reported in this paper provides these chiral auxiliaries with improved yields and a remarkable reduction on the reaction times, particularly in the case of thiazolidine-2-thiones, as compared with the conventional methods. All the auxiliaries prepared here show spectroscopic data in full agreement with those previously reported in the literature

Synthesis of 3-oxo-3-phenyl-2,2,5-trimethyl-1,3-oxaphosphorinanes and their tetrafluoroborate salts

The synthesis and characterization of cis- and trans-3-oxo-3-phenyl-2,2,5-trimethyl-1,3-oxaphosphorinanes (7a and 7b) and their corresponding tetrafluoroborate salts (3a and 3b), heterocyclic organophosphorus compounds not previously reported in the literature, was accomplished. They were fully characterized by H, C and P NMR. It was established the relative configuration of these compounds on the basis of an X-ray diffraction study of oxide 7a

Preparation of Phosphostatine Analogues From L-amino acids

Reduction of (3S)-N,N-dibenzylamino-2-ketophosphonates 9a-d derived from L-amino acids was carried out with catecholborane at -20 oC to afford the (3S)-N,N-dibenzylamino-(2R)-hydroxy-phosphonates syn-10a-d, whereas the reduction of (3S)-N-benzylamino-2- ketophosphonates 13a-d with Zn(BH4)2 at -78 oC yield (3S)-N-benzylamino-( 2S)-hydroxyphosphonates anti-14a-d. The reduction in both cases was in good chemical yields and with high diastereoselectivity. The hydrolysis and hydrogenolysis of 10a-d and 14a-d afford the (3S)-amino-(2R)-hydroxyphosphonic acids 6 and (3S)-amino-(2S)- hydroxyphosphonic acids 7, respectively, which are analogues of phosphostatine

Syntbesis of 3-0xo-3-pbenyl-2,2,5-trimetiiyl-l,3-0xapbospborinanes and tbeir tetrafluoroborate salts

The synthesis and characterizationof cis- and trana- 3-oxo-3-pbenyI-2,2,5-trimethyI-l,3-oxapbospborinanes (7a and 7b) and tbeir corresponding tetraf1uoroborate salts (38 and 3b), heterocyclic organ.ophosphorus compounds not previously reported in the literature, was accomplished. Theywere fully characterized by 1H, 13C and 31PNMR. Itwas established the relative configuration ofthese compounds on the basis of an X -ray diffraction study of oxide 7a