Design, synthesis, and fungicidal activity of macrolactones and macrolactams with a sulfonamide side chain.

Four series of novel macrolactones and macrolactams12-alkylsulfonamido-1,15-pentadecanlactones ( 5), 12-alkylsulfonamido-15-methyl-1,15-pentadecanlactones ( 6), 12-alkylsulfonamido-1,15-pentadecanlactams ( 7), and N-(alkylsulfonamidoethyl)-1,12-dodecanlactams ( 8)were designed and synthesized from readily available 2-nitrocyclododecanone or cyclododecanone. Their structures were confirmed by (1)H NMR, IR, and elemental analysis. The bioassay showed that these compounds displayed fair to excellent fungicidal activity against Rhizoctonia solani Kuhn and have a gradual increase of fungicidal activity in the order of 6, 7, 8, and 5. Among them, compounds 5a, 5b, and 5c displayed excellent fungicidal activity against R. solani comparable with the commercial fungicide carbendazim. Above results illustrated that the rule on the relationship between the activity and hydrogen-bonding, namely the macrocyclic compounds with a hydrogen-bonding acceptor and a hydrogen-bonding donor on the ring and having a three methylenes distance between two polarizable groups have the best fungicidal activity against R. solani, has a general suitability to the macrocyclic compounds, and pesticide molecules may combine with a target enzyme by hydrogen-bonding. The facts, which compound 6 has a much lower fungicidal activity against R. solani than compound 5 but their difference in chemical structure is only that there is a methyl group on the C15 for compound 6 and none but hydrogen atom on the C15 for compound 5, indicated that a methyl group plays an inhibitory role to the fungicidal activity. It suggests that the existence of a methyl group with a great volume between two polarizable groups would interfere in the interaction of pesticide molecules and the target enzyme.

Synthesis and biological activities of 2-oxocycloalkylsulfonamides.

A series of novel 2-oxocycloalkylsulfonamides (4) were synthesized and their structures confirmed by IR, (1)H NMR, and elemental analysis. The bioassay showed that they have fair to excellent fungicidal activities against Botrytis cinerea Pers and Sclerotinia sclerotiorum. Among them, compounds 4A(10), 4A(11), 4A(12), 4B(2), and 4B(3), the EC(50) values of which were 2.12, 3.66, 3.96, 2.38, and 2.43 microg/mL, respectively, displayed excellent fungicidal activity against B. cinerea Pers, and are comparable with commercial fungicide procymidone (the EC(50) value is 2.45 microg/mL). 3D QSAR against B. cinerea Pers was studied, a statistically significant and chemically meaningful CoMFA model was developed and some compounds which have a high predicted activity were forecasted. In addition, the bioassay also showed that the compounds have good inhibitory activities against human tumor cells HL-60, BGC-823, Bel-7402 and KB. It is interesting to point out that the antitumor activities of compounds 4 are in accordance with their fungicidal activity to a great extent: compounds having relatively best antitumor activities (4A(10), 4A(11), 4A(12), and 4B(3)) also displayed excellent fungicidal activity.

Synthesis and fungicidal activity of macrolactams and macrolactones with an oxime ether side chain.

Three series of novel macrolactams and macrolactones--12-alkoxyimino-tetradecanlactam, 12-alkoxyiminopentadecanlactam, and 12-alkoxyiminodecanlactone derivatives (7A, 7B, and 7C)--were synthesized from corresponding 12-oxomacrolactams and 12-oxomacrolactone. Their structures were confirmed by 1H NMR and elemental analysis. The Z and E isomers of 7A and 7B were separated, and their configurations were determined by 1H NMR. These compounds showed fair to excellent fungicidal activities against Rhizoctonia solani Kühn. It is interesting that the Z and E isomers of most of the compounds have quite different fungicidal activities. The fact that the compounds have a gradual increase of fungicidal activity in the order of 7A, 7C, and 7B indicated that the macrocyclic derivatives with a hydrogen-bonding acceptor (=N-O-) and a hydrogen-bonding donor (-CONH-) on the ring, and a three methylenes distance (CH2CH2CH2) between these two functional groups, exhibited the best fungicidal activity. The bioassay also showed that 7B not only has good fungicidal activity but also may have a broad spectrum of fungicidal activities.