Papaverinium chloride

Alkylpapaverinium salts, often called papaverine methochloride, etho-sulfate, etc., are prepared readily from the base and alkyl halides, sulfates, etc., by standard methods. Their reduction furnishes iV-alkyltetrahydro-papaverines (21, 27, 28). For example, iV-methylpapaverinium sulfate yields DL-laudanosine (XIII) on cathodic reduction (29) another publication records an almost quantitative yield of XIII by reduction of methyl-papaverinium chloride with zinc-cadmium alloy and acetic-formic acid (28). 

Mit 1-Amino-propan erhalt man analog das 13-Methyl-9-propylamirw-2,3,IQ-trimethoxy-5,6-dihydro-(dibenzo aig]chinolizinium)-chlorid mit Pyrrolidin und einigen anderen Ami-nen verlauft die Reaktion anders. N-Methyl-papaverinium-jodid laBt sich mil 2-Amino-ethanol, wie oben beschrieben, unter Austausch nur einer Methoxy-Gruppe in l-(3,4-Dimethoxy-benzyl)-6-(2-hydroxy-ethylamino)-7-methoxy-2-methyl-isochmolinium-jodid (90%) uberfiihren1. 

A patent for the preparation of quaternary salts of papaverine from C5, Ce, and Cg halides been published. N-Alkyl-papaverinium salts have been found to undergo oxidation by oxygen either photolytically or in the presence of cuprous chloride, to give the isoquinolones (25). The corresponding dihydro-papaverinium salts (26), with oxygen and cuprous chloride, do not suffer fission, and oxidation of the N-methyl compound (26 R = Me) in this way, followed by reduction of the product with sodium borohydride, affords a- and -hydroxy-laudanosines 21) The n.m.r. spectrum of laudanosine has been studied in detail. 

Quaternary papaverinium salts (22) have been converted into enamines (23), which have been oxidised by singlet oxygen or by oxygen and cuprous chloride with fission to the quinolones (24). N-methyl-3,4-dihydropapaverinium salts... 

---