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2,3,4,6-Tetra-O-acetyl-1-O-(2-propenyl)-β-d-glucopyranoside (1a), which is a useful raw material in the synthesis of a bioactive agent, has been synthesized in 50% yield by reacting β-d-glucose pentaacetate and 3 mol equiv of an allyl alcohol with 0.9 mol equiv of ZnCl2 in toluene at 80 °C for 2 h followed by recrystallization from diisopropyl ether. This method is suitable for the large-scale preparation of 1a due to its efficiency, safety, and cost-effectiveness.

The diastereomeric repellents of p-menthane-3,8-diol were produced from citronellal by treatment with 0.25% sulfuric acid at 50 °C for 11 h to give 97.9% conversion and 92.3% selectivity and citronellal acetal by-products with only 2.7%. The crude products were crystallized from n-heptane at −50 °C for 20 h to give p-menthane-3,8-diols in 80% yield and high purity. The stereochemistry of the citronellal acetal by-products was determined by 2D NMR and NOE.

The synthesis of 3-methylalkane-2,4-diones, which are intense strawlike and fruit-flavored compounds, has been performed by the aldol condensation of n-alkanal (C2−C7) and methyl ethyl ketone to give 4-hydroxy-3-methyl-2-alkanones in 31−72% yield, followed by oxidation using sodium hypochlorite in the presence of 4-benzoyloxy-2,2,6,6-tetramethyl-piperidine-N-oxide in 60−86% yield.

The synthesis of β-keto esters has been performed in good yield by reacting excess methyl acetoacetate with barium oxide, acylating the resulting barium complex with acid chloride, and then cleaving the α-acyl β-keto ester with methanol at a mild temperature. Using this new procedure, various β-keto esters were prepared. Thus, methyl 4-phenyl-3-oxobutanoate, methyl 3-phenyl-3-oxopropionate, methyl 4-cyclohexyl-3-oxobutanoate, and methyl 3-oxooctadecanoate were prepared from methyl acetoacetate and the corresponding acid chloride in 69%, 84%, 67%, and 74% yields, respectively.

Background & Aims: The p53 and BAX genes have been linked to apoptosis. p53 was not frequently found to be mutated in colorectal carcinomas with a microsatellite mutator phenotype, but frame-shift mutations in a tract of eight guanines within BAX were frequently found in these carcinomas. To understand the roles of these genes in hereditary nonpolyposis colorectal cancer (HNPCC) tumorigenesis, we examined whether BAX mutations occur in adenoma and carcinoma specimens from patients with HNPCC and also determined the frequencies of p53 mutations. Methods: Thirteen colorectal adenomas and 24 adenocarcinomas from patients with HNPCC showing a microsatellite instability phenotype were screened by polymerase chain reaction followed by denaturing polyacrylamide gel electrophoresis and direct sequencing. Results: Two of the 13 adenomas (15.4%) and 13 of the 24 adenocarcinomas (54.2%) showed mutation patterns and were confirmed to have frame-shift mutations at the BAX repeat site by direct sequencing. For p53, only 1 of the 24 adenocarcinomas (4.2%) showed a missense mutation. Conclusions: In HNPCC colorectal carcinomas, BAX was significantly (P = 0.024) more mutated than in adenomas. p53 was not frequently found to be mutated in these carcinomas. These data suggest that mutations in BAX, rather than mutations in p53, may contribute to the adenoma-carcinoma transition in HNPCC tumorigenesis. GASTROENTEROLOGY 1998;114:268-274

An N-ras-related transforming gene was detected in the human lung carcinoma cell line SW-1271 and molecularly cloned. The lesion responsible for its acquisition of transforming activity was localized to a single nucleotide transition from A to G in codon 61 of the predicted protein. This lesion in the second exon results in the substitution of arginine for glutamine at this position. These findings, together with previous studies, indicate that the activation of ras oncogenes in human tumors is most commonly due to point mutations at one of two major "hot spots" in the ras coding sequence.