Showing papers by "Susumu Kobayashi published in 1988"
TL;DR: Les acylsilanes α-chiraux montrent des preferences diastereofaciales exceptionnelles dans des additions nucleophiles qui sont suivies d'une protodesilylation par l'anion F − for donner des alcools secondaires as discussed by the authors.
Abstract: Les acylsilanes α-chiraux montrent des preferences diastereofaciales exceptionnelles dans des additions nucleophiles qui sont suivies d'une protodesilylation par l'anion F − pour donner des alcools secondaires
55 citations
TL;DR: The findings indicate that the inactivation reaction of PAF present in the extracellular space is mainly catalyzed by plasma acetylhydrolase, which yields lysoPAF.
Abstract: We examined the substrate specificity of PAF-degrading enzymes from various sources using platelet activating factor (PAF) and its synthetic analogs. The results were as follows: 1) Tissue-originated acetylhydrolases, such as rat kidney soluble enzyme, deacetylated 1S-methyl-1-O-hexadecyl-2-acetyl-sn-glycero-3-phosphocholine (1S-Me-PAF) slightly more rapidly than PAF, whereas plasma acetylhydrolase hydrolyzed PAF more effectively than 1S-Me-PAF. 2) Rat polymorphonuclear leukocytes, monocytes, and lymphocytes homogenates showed an appreciable acetylhydrolase activity, the substrate specificity of which resembled that of the plasma enzyme. 3) Pleural exudates in an experimental pleurisy induced in rats by carrageenan contained an acetylhydrolase activity, the properties of which were similar to those of the plasma enzyme. 4) An extracellular phospholipase A2 activity, which was also observed in the pleural exudate and required Ca2+ ion for maximum activity, seemed not to participate in the deacetylation of PAF, since addition of EDTA did not affect the PAF deacetylation catalyzed by the pleural exudate. These findings indicate that the inactivation reaction of PAF present in the extracellular space is mainly catalyzed by plasma acetylhydrolase, which yields lysoPAF.
43 citations
TL;DR: In this article, 3-monosubstituted glutarates are subjected to hydrolysis with pig liver esterase to afford the corresponding chiral half-esters.
19 citations
TL;DR: In this article, a key intermediate to thienamycin is synthesized enantioselectively under complete stereo and regio-chemical control starting from a chiral half ester 5 enzymatically generated.
18 citations
TL;DR: The monoester 6, generated in situ by the enzymatic hydrolysis of the symmetric diester 5a with pig liver esterase, undergoes extremely facile Meinwald-type rearrangement to afford the bicyclo[3.1.0]hex-2-ene derivative 8a in quantitative yield.
16 citations
TL;DR: Clinical findings suggest a possible relationship between exposure of HB virus and FCL, the first case of fibrolamellar carcinoma of the liver (FCL) in the Orient.
Abstract: We describe, in a 56-year-old man, the first case of fibrolamellar carcinoma of the liver (FCL) in the Orient. Contrary to patients seen in the Western world, our patient has many characteristics of ordinary hepatocellular carcinoma seen in the Orient, i.e., middle age, male, HBsAg carrier, elevated alpha-fetoprotein, presence of HBsAg in the hepatocytes, and chronic hepatitis. These clinicopathological findings suggest a possible relationship between exposure of HB virus and FCL.
12 citations
TL;DR: In this article, a key intermediate for the synthesis of monobactam analogues, cis-3-benzyloxycarbonyl-amino-4-(2-hydroxyehtyl)-2-azetidinone was synthesized from (4S)-4-methoxy carbonylmethyl-2-enzyloxy-acetamido, and converted into monobacts having a methoxyethyl group at the C-4 position of the β-lactam ring.
Abstract: As a key intermediate for the synthesis of monobactam analogues, cis-3-benzyloxycarbonyl-amino-4-(2-hydroxyehtyl)-2-azetidinone was synthesized from (4S)-4-methoxycarbonylmethyl-2-azetidinone, and converted into monobactams having a methoxyethyl group at the C-4 position of the β-lactam ring. Among the compounds synthesized, disodium (3S, 4R)-3[2-(2-aminothiazol-4-yl)-(Z)-2-carboxymethoxyiminoacetamido]-4-(2-methoxyethyl)-2-azetidinone-1-sulfonate showed strong activity against a variety of gram-negative bacteria except Pseudomonas aeruginosa. Furthemore, the 4-methoxyethyl derivatives exhibited excellent stabiliy to β-lactamases, and the syntheses of the corresponding trans isomer and 3α-methoxy derivatives are also described.
11 citations
TL;DR: In this article, cyclohexene derivatives, 8 ~ 11, fused to γ-lactone with angular methyl are efficiently prepared in an enantio-, stereo, and regioselective manner from the chiral monoester.
5 citations
TL;DR: Benign, primary lipogenic tumors of the liver have a relatively characteristic ultrasonographic and CT appearance, and accordingly, these two procedures seen likely to be of value in the qualitative diagnosis of these tumors when used in combination.
Abstract: We experienced a case of hepatic angiomyolipoma, a tumor of exceedingly rare occurrence. The patient was a 68-year-old woman who had been kept under medical surveillance since the age of 52 years. In July 1986, after developing a fever of about 1 week's duration, she was found to have a well-demarcated homogeneous tumor-like lesion of high luminescence in the right hepatic lobe on ultrasonography. CT showed the lesion as a low-density area having a CT value of -30-50 HU. As the tumor, initially suspected to be lipogenic, was possibly malignant, partial hepatectomy was performed. Pathological examination led to a diagnosis of hepatic angiomyolipoma.This neoplastic entity appears to be exceedingly rare, only 23 cases having been reported so far in Western countries and 10 cases documented in Japan. Benign, primary lipogenic tumors of the liver have a relatively characteristic ultrasonographic and CT appearance, and accordingly, these two procedures seen likely to be of value in the qualitative diagnosis of these tumors when used in combination. Such benign tumors of hepatic origin may be difficult to distinguish from liver cell carcinoma that has undergone fatty degeneration and caution should therefore be exercised to avoid confusion. In dealing with hepatic tumors it is important to make a correct qualitative diagnosis with the aid of suitable means, such as diagnostic imaging, and hepatic angiomyolipoma must be comsidered in differential diagnosis.
2 citations
TL;DR: In this paper, a key intermediate for the synthesis of monobactam analogues, cis-3-benzyloxycarbonyl-amino-4-(2-hydroxyehtyl)-2-azetidinone was synthesized from (4S)-4-methoxy carbonylmethyl-2-enzyloxy-acetamido, and converted into monobacts having a methoxyethyl group at the C-4 position of the β-lactam ring.
Abstract: As a key intermediate for the synthesis of monobactam analogues, cis-3-benzyloxycarbonyl-amino-4-(2-hydroxyehtyl)-2-azetidinone was synthesized from (4S)-4-methoxycarbonylmethyl-2-azetidinone, and converted into monobactams having a methoxyethyl group at the C-4 position of the β-lactam ring. Among the compounds synthesized, disodium (3S, 4R)-3[2-(2-aminothiazol-4-yl)-(Z)-2-carboxymethoxyiminoacetamido]-4-(2-methoxyethyl)-2-azetidinone-1-sulfonate showed strong activity against a variety of gram-negative bacteria except Pseudomonas aeruginosa. Furthemore, the 4-methoxyethyl derivatives exhibited excellent stabiliy to β-lactamases, and the syntheses of the corresponding trans isomer and 3α-methoxy derivatives are also described.
1 citations
TL;DR: Les acylsilanes α-chiraux montrent des preferences diastereofaciales exceptionnelles dans des additions nucleophiles qui sont suivies d'une protodesilylation par l'anion F − for donner des alcools secondaires.
Abstract: Les acylsilanes α-chiraux montrent des preferences diastereofaciales exceptionnelles dans des additions nucleophiles qui sont suivies d'une protodesilylation par l'anion F − pour donner des alcools secondaires
TL;DR: It’s time to dust off the pom-poms and dust off that chalice.
Abstract: 大腸癌肝転移切除症例18例の再発様式について検討した. 根治的肝切除後の再発様式は残存肝再発57%, 肺転移29%, 原発巣局所再発14%であった. 原発巣が左側結腸症例, および肝転移の進展度がH2症例では残存肝における再発が多かった. 肝転移巣の発見時期が同時性と異時性の症例とでは, 同時性に対する肝切除後の再発率が高かった. 肝切除後残存肝再発は半年以内に出現するものが多かった. 18症例中術中に肝所属リンパ節転移を16.7%と高頻度に認め, 肝切除時にリンパ節郭清 (特に肝門部および肝十二指腸間膜リンパ節) を施行する必要性が示唆された. 肝所属リンパ節転移をきたした症例の原発巣はn, v, lyの各因子の進行したものが多かった.