Showing papers by "Susumu Kobayashi published in 1994"

Simple and improved preparation of α-aminophosphonic acid derivatives, key building blocks of phosphonopeptides

Abstract: Strecker-type reaction of an aldehyde, ammonium acetate and diethyl phosphite in ethanol afforded the corresponding diethyl α-aminophosphonate, a key building block of the biologically interesting phosphonopeptides, in moderate to good yield

Enantioselective Cyclopropanation of Allylic Alcohols Catalyzed by a Chiral Disulfonamide-Aluminum Complex

Abstract: A chiral disulfonamide-alkylaluminum complex prepared from (1R,2R)-N,N′-bis(benzenesulfonyl)-1,2-cyclohexanediamine and trialkylaluminum or i-Bu2AlH has been found to catalyze a Simmons-Smith cyclopropanation of allylic alcohols with Et2Zn and CH2I2 to afford the corresponding cyclopropanes in excellent yields with high enantiomeric excesses.

Detection of minus-strand hepatitis C virus RNA in tumor tissues of hepatocellular carcinoma.

Abstract: Background. Recently, the detection of hepatitis C virus (HCV) antibody has been widely performed for clinical serum testing of HCV infection and can be identified in most hepatocellular carcinoma (HCC) cases in Japan. In the current study, the authors detected not only plus-strand but also minus-strand HCV RNA as a template for RNA replication in hepatocytes in the resected tumors of HCC, and they investigated those significant for HCC. Methods. The plus-strand and minus-strand HCV RNA were detected using reverse transcription-polymerase chain reaction after the extraction of RNA from the tumor and nontumor tissues of hepatectomized liver, respectively. Results. The detection of HCV RNA in liver tissues from hepatectomized specimens of 20 cases was as follows: in nontumor regions, both of the plus- and minus-strand HCV RNA were detected in 14 cases. Among those cases, plus- and minus-strand HCV RNA were detected in 11 cases, and in another 2 cases, only plus-strand HCV RNA was found in the tumor regions. Conclusions. These results suggest that HCV RNA is able to replicate in tumor tissues of HCC and may be involved in the development of HCC and also that HCV in remnant hepatocytes may cause the recurrence of HCC as secondary carcinogenesis after hepatectomy.

Dna polymerase alpha inhibitor containing 1-o-acylglycerol-2,3-phosphate derivative as active ingredient

Abstract: PURPOSE: To obtain a DNA polymerase t inhibitor containing a specific acyl glycerolphosphate derivative as an active ingredient and useful for carcinostatic agents. CONSTITUTION: This DNA polymerase α inhibitor contains 1-O- acylglycerol-2,3-phosphate derivative expressed by formula I (R 1 is a 10-30C alkenyl or an alkynyl; M is H or a pair cation). Furthermore, a l-O- acylglycerol-2,3-phosphate derivative of formula II (R 2 is a 10-30C alkynyl), e.g. 1-O-[(Z)-9-hexadecenoyl]-2,3-O-isopyrideneglycerol is a new compound. The compound of formula II is obtained by reacting, e.g. 2,3-O-isopyrideneglycerol with (Z)-9-hexadecenoic acid in the presence of dicyclohexylcarbodiimide. COPYRIGHT: (C)1995,JPO

Production of 1-o-acylglycerol 2,3-phosphate

Abstract: PURPOSE:To efficiently obtain the subject compound useful as an antitumor agent, etc., in high yield by reacting a specific acylglycerol with a specified phosphorylating agent and hydrolyzing the resultant compound. CONSTITUTION:A 1-0-acylglycerol of formula I (R is 1-30C alkyl or 2-30C alkenyl) is made to react with a phosphorylating agent such as p-nitrophenyl dichlorophosphate of formula II [X is halogen, imidazolyl or triazolyl; X is halogen, imidazolyl, triazolyl, (substituted)phenoxy, etc.; X is imidazolyl, triazolyl, (substituted)phenoxy, (substituted)alkoxy, etc.] and the resultant compound is then hydrolyzed to afford the objective compound of formula III [M is H, alkaline (earth) metal, etc.].

Significance of hepatitis-b and hepatitis-c viral sequences frequently detected in hepatocellular-carcinoma tissues

Abstract: Serum HBsAg or anti-HCV were identified in over 90% of hepatocellular carcinoma (HCC) patients in Japan with positive rates approximately 20% and 70%, respectively. In this study, we detected HBV DNA and HCV RNA sequences in tumor or non-tumor tissues obtained from 16 hepatectomized HCC cases, using the polymerase chain reaction (PCR) method for HBV x gene and reverse transcription (RT)-PCR for HCV RNA. Only 3 cases were positive of HBsAg in serum, however, HBV x gene could be detected in the tumor or non-tumor tissues of 13 cases among 16 HCC patients. In two cases, HBV x gene was detected exclusively in tumor or non-tumor tissues. Whereas HCV RNA was detected in both tumor and non-tumor in 9 cases, which results coincided with the anti-HCV testing in sera. These results indicate that HBV x gene might be detected as the integrated form in the liver genomic DNA, while HCV RNA as viremia. The frequent detection of HBV DNA suggests that HBV may be associated with the development of HCC predominantly or cooperatively with HCV.

Mode of Recurrence of Hilar Bile duct Carcinoma, and Importance of Occupational Diagnosis and Liver Functional Reserve Assessment.

Abstract: 1973年5月より1993年12月までに教室で切除しえた肝門部胆管癌63例について再発形式を検討すると, 相対非治癒切除以上においては, 肝側断端再発が57.1%をしめる.hwを0としえた例ではその頻度は少なくhw0を目指した手術の拡大が必要と考えられた.そのためには正確な進展度診断に基づく理想的術式の想定と, 肝予備力検査よりの安全切除限界とのすりあわせが肝要である.肝側への進展度診断には従来の方法に加え, シネ胆管像による動画像, 静止画像による読影が各胆管分岐部の観察を可能とし有用であった.また安全切除限界の決定にはMEGXテストとHPS測定による肝予備力測定が有効である可能性が示唆された.加えてメチオニンーPETは肝の部位別のアミノ酸利用を表現しえると考えられ, 肝の部位別に異なる機能を表現できる新しい指標と成りえると考えられた.

Non-Chelation Controlled 1,3-Asymmetric Induction in β-Chiral Acylsilanes.

Abstract: The diastereoselectivity of nucleophilic addition to β-chiral acylsilanes is examined, and our method is applied to the stereoselective synthesis of calcitriol lactone, a major metabolite of vitamine D 3 .

Enantioselective Cyclopropanation of Allylic Alcohols Catalyzed by a Chiral Disulfonamide‐Aluminum Complex.

Abstract: A chiral disulfonamide-alkylaluminum complex prepared from (1R,2R)-N,N′-bis(benzenesulfonyl)-1,2-cyclohexanediamine and trialkylaluminum or i-Bu2AlH has been found to catalyze a Simmons-Smith cyclopropanation of allylic alcohols with Et2Zn and CH2I2 to afford the corresponding cyclopropanes in excellent yields with high enantiomeric excesses.