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:The chitinase inhibitor/insect ecdysis inhibitor allosamidin and eight allosamidin analogues have been synthesised from simple carbohydrate starting materials. Allosamidin was assayed against T ineola bisselliella (Hummel) larvae and all nine compounds were examined for their e †ects on the development of larvae of L ucilia cuprina (Wiedemann). High larval mortality compared to controls resulted when T . bisselliella and L . cuprina larva were exposed to allosamidin. The (1 ] 3) linked regioisomer, the dimeric analogue and the gluco-conÐgurated dimeric analogue of allosamidin all showed high activity against L . cuprina larvae. The regioisomer, the (1 ] 3) linked isomer and its dimeric analogue, as well as the monomer allosamizoline and its regioisomer, were inactive. These new in-vivo results are consistent with known in-vitro insect chitinase inhibition data, in that greatest larval mortality was exhibited by the best inhibitors.

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Photo -bromination of penta-~-acetyl-P-D-glucopyranose with N-bromosuccinimide in carbon tetrachloride causes specific replacement of H-5, and the 5-bromo-derivative can be isolated crystalline in high yield. By-products of the reaction contain monobromoacetyl and dibromoacetyl groups. When bromine was used as reagent the 5substituted compound was again formed as initial product, but, ultimately, tetra-o-acetyl-a-D-giucopyranosyl bromide and dibromides with halogen substituents at C-1 and C-5, and with both bromine atoms at C-1, were also produced. A two-step route from glucose penta-acetate to 1,2,3,4-tetra-O-acetyI-6-deoxy-~-D-xy/o-hex-5-enose is defined. Since the C-5 epimer of the penta-acetate affords the same products, it is proposed that the initial bromination proceeds by way of a discrete radical at the tertiary site.

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