Structure of the insect phagorepellent azadirachtin. Application of PRFT/CWD [partially relaxed Fourier transform/continuous wave decoupling] carbon-13 nuclear magnetic resonance

Azadirachtin, Insect Ecdysis Inhibitor

“…2 ) The present study was carried out because the crude methanol extract of the A. indica fruit showed potent insect ecdysis inhibitory activity with an artificial diet feeding assay. Azadirachtin was isolated as the active principle.…”

A Spectrophotometric Investigation of the Interaction of Iodine with Dibenzyldiaza‐18‐crown‐6, Aza‐15‐crown‐5 and N‐phenylaza‐15‐crown‐5 in Chloroform Solution

“…It should be noted that the reactant species are uncharged, while the transition state complex [(L¼I + )I 3 -] is charged and therefore, the organization of solvent molecules is increased and entropy of the system is diminished upon complex formation. [22][23][24] The results indicate that the rate of reaction is controlled by entropy variations of system. Thus, in the case of DBzDA18C6 complex, the DS ‡ value is less negative in com- parison with the other complexes, and therefore, its formation reaction proceeds relatively faster than the others.…”

The structure of dihydronimbin

“…The stereochemistries of the protons at C(15) and C(17) of nimbin were assigned by considering all the possible configurations at these points and the effects of their possible coupling patterns on the C(16) protons and then comparing these values with those actually observed (Narayanan & Pachapurkar, 1965). Structures of related natural products, such as deacetylnimbin (Narayanan & Iyer, 1967), nimbolide (Ekong, 1967), vepinin (Narayanan, Pachapurkar, • Sawant & Wadia, 1969), salanin (Henderson, die, Malera & Overton, 1968), vilasinin (Pachapurkar, (12) Kornule & Narayanan, 1974) and azadirachtin (12) (Zanno, Muira, Nakanishi & Elder, 1975), which have (10) (9) many features in common with nimbin, were elucidated (10) largely by PMR spectral analysis and by considering (9) (9) their evident relationship to nimbin. Hence it was con- (8) sidered desirable to perform an X-ray structure deter- (9) mination of a derivative of the parent compound (10) (9) nimbin, so that the structures of all these compounds (10) would stand on a firmer basis.…”