Hydroxamic acid glucosides

Sue, M., Ishihara, A. and Iwamura, H. 2000. Purification and characterization of a hydroxamic acid glucoside beta-glucosidase from wheat (Triticum aestivum L.) seedlings. Planta 210, 432-438... 

Givovich, a., S. Morse, H. Cerda, H. M. Niemeyer, S. D. Wrat-TEN, and P. J. Edwards, Hydroxamic acid glucosides in honey-dew of aphids feeding on wheat, J. Chem. Ecol., 18, 841-846 (1992). 

Benzoxazolin-2(3H)-one is a phytotoxic allelochemical resulting from a two step degradation and root exudation process based upon an acetal glucoside of the 2,4-dihydroxy-2H-1,4-benz-oxazin-3(4H)-one skeleton. Such benzoxazinoids or cyclic hydroxamic acids occur in Acanthaceae, Poaceae, Ranunculaceae, and Scrophulariaceae. Their aglucones and resulting benzoxazolinones act as a plant s... 

These early findings, together with the ability to act as plant resistance factors towards pests, led to a cascade of some hundred papers dealing in an interdisciplinary manner with all aspects of benzoxazinoids. This name seems to be more correct than the name cyclic hydroxamic acids, which has often been used to name this class of compounds. However, it is not exact from the structural point of view, because it omits the fact that also a variety of acetal glucosides with lactam units was found in plants. They also may be split enzymatically to form lactam aglucones, but cannot undergo chemical decay into benzoxazolin-2(3H)-ones. Benzoxazinoids occur in Acanthaceae, Ranunculaceae, Scrophulariaceae,... 

Because this paper deals in particular with benzoxazolinone chemistry, we will only present a survey of naturally occurring acetal glucosides with cyclic hydroxamic acid moieties (Fig. 4.2) as precursors of aglucones (Fig. 4.3) which may decompose to (substituted) benzoxazolin-2(3H)-ones (Fig. 4.4). 

Natural benzoxazinone acetal glucosides with cyclic hydroxamic acid unit. 

Baumeler, A., Hesse, M., and Werner, C. 2000. Benzoxazinoids - cyclic hydroxamic acids, lactams and their corresponding glucosides in the genus Aphelandra (Acanthaceae). Phytochemistry 53, 213-222... 

Cyclic hydroxamic acids (11.50) stored in corn and wheat seedlings as their glucosides are released by a glu-... 

A series of hydroxamic acid derivatives with 4-hydroxy-l,4-benzoxazin-3-one structures occur in a number of cereal grain species (Poaceae or Gramineae) (Fig. 7.8) (Niemeyer, 1988). These compounds usually occur in plants as the 2-3-(9-D-glucosides enzymes that hydrolyze the compounds usually co-occur. DIBOA [2,4-dihydroxy-1,4(2H)-benzoxazin-3-one] (22) is the major compound in rye and DIMBOA [2,4-dihydroxy-7-methoxy-1,4(2H)-benzoaxa-... 

Glucosinolates, Cyanogenic Glucosides and Cyclic Hydroxamic Acids... 

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