are filtered off under suction and recrystallized twice from ethanol; yield 89%, m. p. 156--160°C.

( 3 a ) (1.35 g, 5 mmol) is added at room temperature to concentrated hydrochloric acid (25 ml) ; after 3 minutes' stirring the precipitate of ( 5 ) is recovered by filtration (glass suction filter). The crude crop of ( 5 ) is recrystallized from CCl,/CHCl, (or glacial acetic acid); yield 68-75%, m. p. 149-151 "C.

Received: October 18,1971 [Z 537 IE] German version: Angew. Chem. 84,110 (1972)

Dehydro N-Mannich Bases[***] By A p e d Kreutzberger and Mehmet U w a n Uzbek'']

In the Mannich reaction an active compound is allowed to react with formaldehyde and an amine. If the active com- ponent contains a nitrogen atom bearing a reactive hydro- gen, N-Mannich bases are formed. Compounds containing a primary amino group, such as urea"] or benzamide''], have also found special use in this type of reaction.

We have now found that when s-triazine (2) is employed instead of formaldehyde, an analogous condensation takes

X-N RAsA: +

H

Cpd. X R Y Yield M. p. ("C) (%)

( S a ) C,H,-C H CH, 40 124-1 25 ( 5 6 ) N HS CH, 68 230 ( S c i N HS 0 71 218

Cpd. R' RZ Y Yield M. p. ("C) (%)

( 7 a ) Br H CH, 76 114 ( 7 6 ) H c1 0 83 104-105

p] Prof. Dr. A. Kreutzberger and Dr. Mehmet Umran Uzbek [**] Institut fur pharmazeutische Chemie der Universitat 44 Miinster, Hittorfstrasse 58-62 (Germany)

[**I As guest from the Institute of Pharmaceutical Chemistry of the University of Istanbul (Turkey). [***I This work was supported by the Deutsche Forschungsgernein- schaft and the Fonds der Chemischen Industrie.

place with formation of N-Mannich bases ( 5 ) having two hydrogen atoms less. This finding is based on the results of a series of investigations on the aminoinethinylation reaction, in which e.g. anthranilic acid can be converted into 4-quinazolone by reaction with s-triazineE3!

If 2-aminothiazoles or -thiadiazoles of type ( I ) are used in place of anthranilic acid and its derivatives, either no reac- tion takes place or, as in the case of 2-amino-4-phenyl- thiazole ( l a ) , only small yields of the expected N,N'-di- substituted formamidine derivatives are obtained. When, however, attempts were made to increase the yields by addition of excess amine, e. g. piperidine or morpholine, the dehydro N-Mannich bases ( 5 ) were formed, presum- ably via the route shown in the reaction scheme.

2-Aminobenzothiazoles (6) can be converted in an analo- gous way into the dehydro N-Mannich bases (7).

The previously described three-component reactions in which the parent compound or derivatives of phenylaceto- nitrileI4I, of picoline N-oxidesEsl, anilineE6], f l~orene '~] , and phenylhydraziner7' contain the active hydrogen atom, can also be classed under the present, general type of reaction leading to dehydro Mannich bases.

Received: October 21, 1971 [Z 538 IE] German version: Angew. Chem. 84,109 (1972)

[l] A . Einhorn and E. Sprdngerts, Llebgs Ann. Chem. 361, 139 (1908). [2] H . Hellmann and G . Haas, Chem. Ber. 90, 50 (1957). [3] A . Kreutzberger and M . U . Uzbek, Arch. Pharmaz., in press. [4] A . Kreutzberger and D. Abel, Arch. Pharmaz. 301, 881 (1968). [S] A. Kreutzberger and D. Abel, Arch. Pharmaz. 302, 701 (1969). [6] A. Kreutzberger and M . F. G. Steoens, J. Chem. SOC. C 1969, 1282. [7] A. Kreutzberger and D. Abel, Arch. Pharmaz. 303, 107 (1970).

Tetraorganofluorophosphoranes

By Hubert Schmidbaur, Karl-Heinz Mitschke, and Johann Weidlein"]

Of the four conceivable organofluorophosphoranes R,PF,-, having n=1-4 only the types RPF,, R,PF,, and R,PF, are adequately known[']. Hitherto only scatter- ed references have appeared in the literature['] concerning tetraorganofluorophosphoranes, which may be assumed to exist only in a ionic isomeric form, as phosphonium fluorides R,P+F-. It would appear that [(C6H,),P]F[31 and [(C6H5),PC2H5]FE2] are the only representatives ever to have been obtained in a pure state (by halogen exchange from other phosphonium salts in both cases). However, this technique usually runs into considerable experimental difficulties.

Syntheses of pure, salt-free ylidesL4. and their silylated derivativesr6] have now opened up a direct route to com- pounds of formula R,PF. Addition of anhydrous hydro- fluoric acid to corresponding ylides gives the desired prod- ucts just as smoothly as desilylation of the silyl ylides with subsequent H F addition in situ, as formulated for tetra- methylfluorophosphorane ( I ) :

['I Prof. Dr. H. Schmidbaur and DipLChem. K.-H. Mitschke Institut fur Anorganische Chemie der Universitat 87 Wurzburg, Landwehr (Germany) Doz. Dr. J. Weidlein Institut fur Anorganische Chemie der Universitat 7 Stuttgart 1, Schellingstrasse 26 (Germany)

144 Anyew. Chem. internal. Edit. / Vol. 11 (1972) / No. 2