|Budget Amount *help
¥3,400,000 (Direct Cost : ¥3,400,000)
Fiscal Year 1999 : ¥500,000 (Direct Cost : ¥500,000)
Fiscal Year 1998 : ¥900,000 (Direct Cost : ¥900,000)
Fiscal Year 1997 : ¥2,000,000 (Direct Cost : ¥2,000,000)
Allopurinol is known to inhibit xanthine oxidase (XO) and is now widely employed in treatment of gout and hyperuricemia resulting from uric acid. Allopurinol is relatively non-toxic. However, some allopurinol toxicities and a life-threatening toxicity syndrome have been reported after its use. Although XO inhibitory activities have recently discovered in some synthetic compounds, no clinically effective XO inhibitors for the treatment of hyperuricemia have been developed since allopurinol was introduced for clinical use in 1963. Here we established new, convenient, and general syntheses of 7H-purines, 7-β-D-ribofuranosyl-7H-[1, 2, 4]triazolo[3, 4-I]purines, 9H-1, 2, 4-triazolo[3, 4-I]purines, 1H-pyrazolo[3, 4-d]pyrimidines and 7H-pyrazolo[4, 3-e]-1, 2, 4-triazolo[4, 3-c]pyrimidines as new class of potential XO inhibitors.
Their inhibitory activities against bovine milk xanthine in vitro were investigated, and the above compounds prepared in this study exhibited mostly from several times
to several hundred times more potent activities than allopurinol.
(1) The introduction of arylaldehyde hydrazones at the 6-position of 7H-purine-2(3H)-one and at the 4-position of 1H-pyrazolo[3, 4-d]pyrimidin-6(7H)-one markedly increased their activities, being from 10-fold to 900-fold more active than allopurinol. In contrast the 2-oxo derivatives of the purine and the 6-xo derivatives of the pyrazolopyrimidine, the derivatives substituted by a chloro, amino or thioxo group at the 2-position or at the 6-position showed a tendency to decrease the activity.
(2) The tricycle heterocycles, 9H-1, 2, 4-triazolo[3, 4-I]purines, generally showed more potent inhibitory activities than that of allopurinol, but less inhibitory activities compared with the purines.
(3) The tricyclic heterocycles, 7H-pyrazolo[4, 3-e]-1, 2, 4-triazolo[4, 3-c]pyrimidin-5(6H)-ones, showed mostly potent inhibitory activities, being from 30-fold to 800-fold more active than allopurinol and some compound showed a 760-fold more potent activity than that of allopurinol.
It was demonstrated that the oxo group and the arylmethylidenehydrazino group on the ring of the above heterocycles might be important for the inhibitory activity. Less