The previously unknown symmetrical dihalides 1,l-diiodopropane and l,l-diiodo-2-methylpropane, have been synthesized by treatment of the corresponding diazoalkane with iodine. The new asymmetrical dihalides, 1-chloro-1-iodopropane and 1-bromo-1-iodopropane, have been obtained by halodecarboxylation of a-chlorobutyric and a-bromobutyric acid, respectively, with lead tetraacetate in the presence of iodine. Nmr spectral data for these and other geminal dihalides are presented and discussed.

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Methylpyrrolidine and seobutylamine were the most active of 50 nonaromatic amines tested in their cationic form for inhibition of germination of Penicillium digitatum spores. Pyrrolidine, 2-methylpyrrolidine, isopropylamine, l-methyl-2-propenylamine, and cyclobutylamine showed lesser activity, but all other simple amines tested were not inhibitory. Replacement of the C-l or C-4 methyl group of seobutylamine with CF3, CC13, COOH, OCH3, CH2OH, Cl, NH2, or OH resulted in compounds which were not active. ( -)-seoButylamine was considerably more active than the (+) enantiomer, both in preventing spore germination and in inhibiting mycelial growth of three species of fungi which were sensitive to racemic seobutylamine. (-)-seoButylamine and 3-methylpyrrolidine were uniquely effective in preventing infection of citrus fruits by P. digitatum. The receptor site for inhibitory amines on the fungus cell appears to consist of an anionic component which binds the -NH3+ group and a hydrophobic area which is complementary to the sec-butyl radical as spatially oriented in (-)-seobutylamine.The antifungal properties of aliphatic amines, guanidines, and quaternary ammonium compounds with more than ten carbon atoms are well known (Byrde, 1969), but lower aliphatic amines in their cationic form are not generally considered to be fungitoxic by usual standards of comparison. sec-Butylamine (2-aminobutane) was found to be anomalous

The fungistatic activity against Penicillium digitatum and Diplodia natalensis decreased slightly in ascending a homologous series of alkyl esters of benzimidazol‐2‐ylcarbamic acid from the methyl ester (carbendazim) to the pentyl ester; the hexyl and octyl esters were inactive. 2‐(Acylamino)benzimidazoles were slightly less active than the analogous alkyl benzimidazol‐2‐ylcarbamates. Introduction of a methylene bridge between the benzimidazole ring and the 2‐methoxycarbonylamino group abolished antifungal activity. Methylation of either the carbamate nitrogen or an imidazole nitrogen of carbendazim produced inactive compounds. Replacement of the benzimidazole ring of carbendazim with various other ring systems was accompanied by marked reduction in antifungal activity.

Imines, synthesised by the reaction of sec‐butylamine (SBA, 2‐amino‐butane) with pentan‐2‐one, heptan‐2‐one, octan‐2‐one, undecan‐2‐one, benzaldehyde and 2‐furaldehyde, were evaluated as vapour‐phase treatments to prevent the infection of oranges by Penicillium digitatum. All the imines provided decay control equivalent to SBA when they were introduced into the fruit container at a rate equivalent to 16.4 mg SBA litre−1 air volume. The carbonyl compound component of the imines, tested alone at a five‐fold higher rate, did not reduce fruit decay. All the imines were stable in the gaseous state in dry air. The imines of pentan‐2‐one and undecan‐2‐one were hydrolysed rapidly in a humid environment, indicating that their action against P. digitatum was due to the release of SBA into the atmosphere around the fruit. The instability of the imines of the aliphatic ketones makes them unsuitable as generators of SBA in packages. The imines derived from benzaldehyde and 2‐furaldehyde were stable in moist air, but were hydrolysed to a significant degree on moist filter paper, especially at pH < 7. These aromatic imines were absorbed from the atmosphere by the fruit and were hydrolysed rapidly in water, and in a buffer solution that represented the environment in fresh injuries on fruit. Apparently all the imines tested generated SBA in the fruit environment, and this SBA accumulated at potential infection sites, where it prevented the development of decay.