Mechanism of the interaction of color reagent 1, 3-N, N'-bis-4-(4'-nitro benzenediazo) phenyl squaraine with oxoacid anions

By AM1 method, the interactions between 1, 3-N, N′-Bis-4-(4′-nitro benzenediazo) phenyl squaraine (BNBPS) and several oxoacid anions have been studied on the basis of the proposed model. The mechanism of the color reactions is suggested and the answers to the question of whether or not BNBPS colorates with HCO_3~-, CO_3~(2-), NO_2~(-), NO_3~-, etc. are given. It is theoretically predicted that BNBPS might be used as the color reagent for SO_4~(2-).     

Siladenoserinols M–P,sulfonated serinol derivatives from a tunicate

Four new sulfonated serinol derivatives, siladenoserinols M–P (1–4), were isolated from a tunicate of the family Didemnidae collected in Indonesia. Their chemical structures were elucidated by the interpretation of NMR and mass spectroscopic data. Two of them (2 and 4) were revealed to be disulfonate serinol derivatives, and the others were monosulfonates. Siladenoserinols A (5) and B (6), which we previously isolated from the same tunicate, inhibited the p53–Hdm2 interaction with an IC₅₀ value of 2.0?μM. However, 1–4 did not inhibit the activity. The result suggested that the acetyl group in the bicyclic ketal unit and/or the glycerophospholipid moiety in 5 and 6 were responsible for the inhibition of the p53–Hdm2 interaction.     

Studies on Functionally-substituted Azines. 8. Synthesis and Transformations of 1-Arylsulfonylamido-4-methoxy-6-methylpyrimidines

The action of arylsulfonyl chlorides on 2-amino-4-methoxy-6-methylpyrimidine in pyridine gave 2-arylsulfonylamido-4-methoxy-6-methylpyrimidines, which were alkylated at the amide fragment, while the action of hydrazine hydrate led to nucleophilic replacement of the methoxy group. The resultant hydrazinopyrimidines were converted into azidopyrimidines and N-pyrimidinyldithiocarbazinates. Potassium salt of 2-p-toluenesulfonylamido-4-methoxy-6-methylpyrimidine dithiocarbazinate reacted with dimethyl sulfate to give the S-methyl derivative, while the reaction with chloroacetonitrile gave thiazolidinylaminopyrimidine. The chlorination using N-chlorosuccinimide yielded only 5-chloropyrimidines.     

Ytterbium triflate hydrate catalyzed Michael addition and cyclocondensation of α,β-unsaturated ketones with active methylene compounds

Catalyzed by ytterbium（III） triflate hydrate [Yb（OTf）3.xH20], the Michael addition and cyclocondensation of α,β-unsaturated ketones with active methylene compounds to afford the 1,4-adducts and benzo[b]pyran derivatives, respectively were studied.     

Quantitative determination of phenol derivatives fromOleum thymi

Summary The thymol and carvacrol content inOleum Thymi was determined by densitometry. Phenols were separated on a thin—layer of silica gel using two-step gradient elution. The dependence of measurement time on the amount of phenols was investigated. For comparison, the total phenolic content of the essential oil was also determined by colorimetry, the results indicating that the optimal measurment time at which the following measurements should be performed, is 5 min after the end of heating.     

N‐Germyl derivatives of sulfacetamide and ortho‐(sulfonamido)phenylamines: characterization of N‐[o‐(N′,N′‐dimethylsulfonamido)phenyl]‐N‐dimesitylgermaimine

Triethylgermylation of sulfacetamide occurs on the sulfonamido nitrogen in competition with the 1,2 addition of the starting triethylgermyl dimethylamine on the carbonyl group. Thermal decomposition in the presence of dimethylamine yields N‐triethylgermylsulfanilamide. Stable 1:1 sulfacetamide–DBU and 1:1 sulfacetamide–Et₃N complexes were isolated and fully characterized in the course of dehydrochlorination reactions. o‐Sulfonamidophenylamine yields N,N′‐bis‐triethylgermylated derivatives, whereas o‐(N,N‐dimethylsulfonamido)phenylamine leads to monogermylated compounds. The N‐dimethylaminodimesitylgermyl derivative is thermally stable. Dehydrohalogenation of the N‐dimesitylfluorogermyl compound leads to the thermally stable but water sensitive N‐[o‐(N′,N′‐dimethylsulfonamido)phenyl]‐N‐dimesitylgermaimine. Copyright © 2003 John Wiley & Sons, Ltd.