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Autoxidation of S(IV), in buffered solutions,conforms the rate law (1). The increase in buffer concentration has aRobsd=k5[CdO][S(IV)]2[H+]−1.22 (1)rate decreasing effect. On the other hand, in unbuffered solutions the kinetics obey a different rate law (2).Robsd=(k10+k11[CdO])[S(IV)][H+]−0.5 (2)In both situations, the dissolution of CdO accompanies the autoxidation. A heterogeneous catalytic mechanism involving adsorption of both dioxygen and sulfur(IV) on the surface of CdO particle has been proposed.

The hydroboration of cycloalka-1,3-dienes (CnH2n–4, n= 6, 7 and 8) with diisopinocampheylborane, (dIpc2BH or IIpc2BH) at –25°C provides highly enantiomerically pure B-(cycloalk-2-enyl)diisopinocampheylboranes, I or dIpc2BCnH2n–3( 93% ee). Surprisingly, these allylic borane derivatives retain their stereochemical integrity at –25 °C although such compounds are capable of undergoing racemization through rapid allylic rearrangements. Furthermore, the B-(cycloalk-2-enyl)diisopino-campheylboranes achieve allylborations of aldehydes at –78 °C and afford 1 -(cycloalk-2-enyl)alkan-1- ols in 90–95% ee and 100%syn-diastereoselectivity.

Triethylamine - Methanesulfonyl chloride has been employed as reagent for stereoselective synthesis of 2Z-2-(Chloromethyl)aryl-2-enoates from Baylis Hillman products in good yields at room temperature.

Thiols are the most reactive nucleophilic reagents among the biological models investigated. The reactivity of butenolides 1a–c, 2–4, and 6–8 toward l -cysteine, a model biological nucleophile, was studied spectrophotometrically. The rates of the reactions were measured and correlated with antitumour activity of these molecules. N-Acetylcysteine addition product 5, resulting from the treatment of butenolide 4 with glutathione precursor, N-acetyl- l -cysteine, was isolated. Unlike purine-containing γ-(Z)-ethylidene-2,3-dimethoxybutenolides 1a–c, 4, 6, and 7, adduct 5 and butenolides 10–12 did not exhibit inhibitory activity against murine leukemias (L1210 and P388), breast carcinoma (MCF7), and human T-lymphoblasts (Molt4/C8 and CEM/0) cell lines. As such, the biological activity of purine-containing butenolides can be attributed to their adenine moiety as a recognition site as well as their reactivity towards the cysteine residues of functional proteins forming covalent bond via reverse Michael type addition. Adenine-containing phosphonothioanhydride derivative 8 was also synthesised. Its reaction with N-acetyl- l -cysteine produced N,S-diacetylcysteine and thiophosphonate 9. Compound 9 did not exhibit anticancer activity; yet its precursor 8 displayed the most pronounced inhibition on all the examined malignant tumour cell lines. In the presence of l -cysteine, cytotoxicity of 4 and 8 was decreased, whereas glutathione addition more influenced on the cytotoxicity of 8. It was found that adenine-containing phosphonothioanhydride 8 functions as a significant irreversible inactivator of the Escherichia coli ribonucleoside diphosphate reductase. After treatment of MCF7 cells with compound 8, fluorescence microscopy demonstrated the presence of nucleus shrinkage or segmentation. This apoptotic morphology, however, was not pronounced in the presence of glutathione or dithiotheritol.

A facile, mild, and efficient methodology for the ionic Diels–Alder reaction of acetals of α,β‐unsaturated ketones and aldehydes as dienophiles with various 1,3‐dienes employing MgBr2 as the Lewis acid catalyst to furnish corresponding Diels–Alder adducts at ambient temperature is described.

Relative Lewis acidities of (+)-Pr(hfc) 3 , (+)-Eu(hfc) 3 and (+)-Yb(hfc) 3 have been estimated by measuring the induced chemical shift of the aldehydic proton of benzaldehyde in the presence of these lanthanide complexes.The order has been estimated as Pr(hfc) 3 >Yb(hfc) 3 >> Eu(hfc) 3 . These lanthanide complexes and a few other non-lanthanide compounds such as BBr 3 , BF 3 .OEt 2 , TiCl 4 and SnCl 4 have been used as Lewis acid catalysts in a coupling reaction between an aldehyde and (E)-1-methoxy-1-(trimethylsilyloxy)propene. Results show that the chemical yield of the reaction is in the same order as the Lewis acidity of the catalyst used. The observation is in consonant with the expectation that higher is the Lewis acidity more should be degree of activation of the carbonyl base by the Lewis acid.