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Summary. Two new syntheses of pyrazolo[l, 5-al-s-triazincs are rcported : a) Addition of acetyl isocyanate t o 5-amino-3-methyl-pyrazolc followed by hydrolysis yields N-(3-methyl-5-pyrazolyl)-urea (15), which on cyclisation with triethyl orthoacetate gives 2-hytlroxy-4.7-di-

Canine saphenous veins were investigated in vitro either within 24 h after removal or after storage at −190°C for 4–5 weeks in foetal calf serum containing 1.8 m dimethyl sulphoxide. Contractions and 45Ca2+ uptake in response to both depolarization and guanfacine were studied in the absence and presence of the calcium channel antagonists diltiazem, verapamil, nifedipine and the two stereoisomers of a 1,4‐dihydropyridine derivative, namely the (+)−(S) enantiomer and the (−)−(R) enantiomer of 202–791 (isopropyl 4‐(2,1,3‐benzoxadiazol‐4‐yl)‐l,4‐dihydro‐2, 6‐dimethyl‐5‐nitro‐3‐pyridinecarboxylate). Comparison of the data obtained on unfrozen and frozen/thawed veins revealed a good preservation of both contractile responsiveness and 45Ca2+ uptake mechanisms after storage at −190°C. It is suggested that cryopreservation is a useful technique for storing venous smooth muscle for pharmacological studies.

918HELVETICA CHlMICA ACTA 9-(~-Didthylarni~zo-athyl)-l-hydroxy-l, 3-dimethyl-l12, 3,4-tetvahydvo-y-carbolan (X V I I ) : Behandelt man 8,16 g der oben beschriebenen sekundaren Base in 13 ml Eisessig mit 2,7 ml 40-proz. A new synthesis of y-carbolines is described. Starting from 2-lithium l-alkylindoles, reaction with an a-dialkylaminoketone yields 2-indolylethanolamines, which are aminomcthylated with formaldehyde and dimethylamine in the 3-position of the indole nucleus. The dimethylaminomethyl nitrogen of this gramine derivative may be selectively quaternized with methyl iodide and the quaternary gramine derivative cyclized to N(b)-quaternized 1-hydroxy-1 ,2,3,4-tetrahydro-y-carboline derivatives by hcating. Thc latter products may be aromatized at higher temperatures to quaternary y-carboline derivativcs. The generality of thc new method is verified by numerous examples.Forschungslaboratorien der CIBA AKTIENGESELLSCHAFT, Basel Pharmazeutische Abteilung