78477-86-8Relevant academic research and scientific papers
Efficient method for the deprotection of tert-butyldimethylsilyl ethers with TiCl4-Lewis base complexes: Application to the synthesis of 1β-methylcarbapenems
Iida, Akira,Okazaki, Hiroki,Misaki, Tomonori,Sunagawa, Makoto,Sasaki, Akira,Tanabe, Yoo
, p. 5380 - 5383 (2007/10/03)
TiCl4-Lewis base (AcOEt, CH3NO2) complexes smoothly deprotected tert-butyldimethylsilyl (TBDMS) ethers. The reaction velocity with these complexes, which seemed less reactive due to the influence of Lewis bases, was considerably greater than that with TiCl4 alone. Selective desilylations between aliphatic and aromatic TBDMS ethers (1 and 5), between 1 and benzyl, allyl, tosyl, methoxyphenyl, and chloroacetyl ethers (13, 14, 15, 16, and 17), and between TBDMS and TBDPS ethers (18 and 19) were successfully performed. Desilylation of TBDMS-aldol, acyloin, and β-lactam analogues 9-12 proceeded smoothly due to anchimeric assistance by the neighboring carbonyl groups. The present method was successfully applied to the practical synthesis of 1β-methylcarbapenems 20a′-f′.
Simple and Condensed β-Lactams. Part 23. Synthesis of Some Compounds Related to the Monobactams, Carrying Non-Acylamino Substituents in Position 3 and Various Heterocyclyl or Heterocyclylmethyl Substituents in Position 4 of the β-Lactams Ring
Fetter, Jozsef,Bertha, Ferenc,Czuppon, Tibor,Kajtar-Peredy, Maria,Lempert, Karoly
, p. 2738 - 2789 (2007/10/03)
Racemic monobactam analogues 8a-8c, 8e-8g, 8n, 27, 44k-44m, 48c and 51d, carrying hydrogen or non-acylamino substituents in position 3, and 2-substituted thiazol-4-yl, 2-substituted thiazol-4-ylmethyl, 4-substituted yhiazol-2-ylmethyl, 2-benzyltetrazol-5-ylmethyl or 5-methoxyisoxazol-3-ylmethyl substituents in position 4 of the β-lactam ring, as well as the reversed monobactam 35 were synthesised.None of the compounds synthesised exhibited any microbiological activities.Base catalyzed rearrangement of a 4-cyanomethylazetidin-2-one (39j) into a 6-aminopyridin-2(1H)-one (40) and acid catalyzed rearrangements, with elimination of the lactam nitrogen atoms, of two 4-(thiazol-2-ylmethyl)azetidin-2-ones (44a, 44b) into a thiazolopyridinone (47) were observed.
Stereoselective reactions. XX. Synthetic studies on optically active β-lactams. III. Stereocontrolled synthesis of chiral intermediate to (+)-thienamycin from D-glucose
Ikota,Yoshino,Koga
, p. 2201 - 2206 (2007/10/02)
A chiral key intermediate (19a) for the synthesis of (+)-thienamycin was synthesized starting from D-glucose. The enol ether 13, obtained from the ketone 11 by Horner-Wittig reaction, was transformed to the corresponding methyl ester 16 by pyridinium chlorochromate oxidation or by employing the Wacker process. The ester 16 was further converted to the β-lactam 19a, which is a useful chiral precursor to (+)-thienamycin.
Stereocontrolled synthesis of (+)-thienamycin from 3(R)-hydroxybutyric acid
Iimori,Shibasaki
, p. 1523 - 1526 (2007/10/02)
The vinyloxyborane(5), prepared from (+)-S-phenyl-3(R)-butanethioate, 9-BBN triflate and diisopropylethylamine, reacted with N-(3-benzyloxypropylidene)benzylamine to give the β-benzylamino thiol ester(6) in a moderate yield, which was efficiently converted to the optically pure thienamycin intermediate(10).
A PRACTICAL SYNTHESIS OF (+/-)-THIENAMYCIN
Melillo, D.G.,Shinkai, I.,Liu, T.,Ryan, K.,Sletzinger, M.
, p. 2783 - 2786 (2007/10/02)
An efficient and operationally simply synthesis of (+/-)-thienamycin is described.
