4-Aryl-4-oxazolin-2-ones exhibiting myotonic and myorelaxing activity
United States Patent 1 Bottari et al.  
 [451 Apr. 22, 1975 Francesca Serafini, C arrara; Natale Tellini, Pisa, all of ltaly [73] Assignee: Messrs. Laboratorio Guidotti &amp; C. S.p.A., Pisa. ltaly [22] Filed: Feb. 3, 1972 [21] Appl. No.: 223,090  
 [30] Foreign Application Priority Data Feb. 8, 1971 Italy 452l0/7l [52] US. Cl 260/307 C; 260/482 C; 260/592;  
  424/272 [51] Int. Cl C07d 85/38 [58] Field of Search 260/307 C [56] References Cited FORElGN PATENTS OR APPLICATIONS 1.496.594 9/1967 France OTHER PUB LlCATlONS Bottari et al.. J. Med. Chem. 1972, 15(1). 3940. Huisgen et al.. CA. 63. l6337d. h( I965). Saettone et al.. CA. 66, 94936x (I967).  
 Primary Examiner-Donald G. Daus Assistant E.\-aminer-Raymond V. Rush Altorney. Agent. or Firm-Steinberg &amp; Blake [57] ABSTRACT Therapeutically active compounds for use as agents stimulating and depressing muscular tone and central nervous system. having as formula 3 Claims, No Drawings 4-ARYL-4-OXAZOLIN-2-ONES EXHIBITING MYOTONIC AND MYORELAXING ACTIVITY This invention relates to a series of 4-aryl-4 oxazolin- Z-ones and to methods for preparing the same.  
  The compounds according to the invention have been found to be useful therapeutic agents. after some of such compounds exhibit a marked stimulating activity on the central nervous system and muscular tone. while other compounds exhibit a sedative and myorelaxing effect. The compounds according to the invention are shown by the following general formula:  
 wherein R may be anyone of the following groups:  
  As shown in Scheme I. the 4-aryl-4-oxazolin-Z-ones l according to the present invention can be produced by cycling. under various conditions. the corresponding 2-aryl-Z-oxoethyl-carbamates (3 In turn. these carbamates can be produced by treating Z-aryl-Z-oxoethanols (2) with phosgene and ammonia (Method :1). or alternatively with sodium isocyanate and trifluoroacetic acid (Method b).  
 SCHEME! 0 fi i&#39;rog o (.2) 06 11- N We E EEC-6004+ I Mot/M68 O O .Q&#39;-QH;D*-NI4 CH5 C00 As shown in Scheme 1. the conversion of the several carbamates into the corresponding 4-oxazolin-2-one&#39;s- The myorelaxing and myotonic activity of the products according to the invention has been discovered and studied by tests in vitro&#34; and in vivo&#34;: in the tests &#34;in vitro&#34; by measuring the contracturing. or antagonistic action thereof to the contractions induced by barium-chloride. on a length of guinea pig ileus maintained in a suitably predetermined bath (test on Magnus isolated organ). as compared with barium-chloride and papaverine. In the tests in vivo.&#34; in addition to ap preciating the changes in the general body tone. the myotonic or myorelaxing activity thereof has been quantitatively estimated. as compared with physostigmine (known natural myotonically active drug) and mephenesine 3-( o-tolyloxy l .2- propanediole:(known myorelaxingly active drug). by experimentally measuring the animal prehension force versus the time of resistance exhibited by them in supporting a metal bar weighing 20 grants.  
 The activity on the central nervous system has been studied through the autocinesis test and extimating the strengthening or the antagonism in the hypnosis as proerence drugs appears at substantially higher doses. such as 0.3 mg/kg physostigmine and 1 mg/kg cardiazole (D.C.l.)  
 (pentetrazole 6,7 .8.9-tetrahydro-5 H- tetrazolazepine) and 7.0 mg/kg guanidine and a stimu- 4-substituted can be accomplished by simple cold dis-&#39; lating activity on the central nervous system. Due to solution in 10% aqueous NaOH and subsequent acidification (Method at), or by prolonged ebullition of carbamate in acetic acid (Method 11). or with p-toluenesulphonic acid (Method c).  
 such pharmacological properties and in view of the low toxicity thereof. some of the compounds according to the invention are advantageous as therapeutic agents suitable in therapy of myoastenias of varying nature and as antifatigue agents. while the 4-naphtyland 4- diphenylyl-4-oxazolin-2-ones are suitable as myorelaxing. antispastic and sedative drugs.  
  By way ofexample the preparation will now be given for some of the compounds according to the present invention.  
 EXAMPLE I 2-phenyl-2-oxo-ethyl carbamate (Formula 3.  
 Method a g 2-phenyl-2-oxo-ethanol were dissolved in a mixture comprising I00 ml anydrous benzene and 20 ml freshly distilled dimethylaniline and slowly added with 40 ml 20% solution of phosgene in toluol. cooling at 0C and stirring. Upon addition completion. the mixture was stirred at room temperature for minutes. then cooled again at 0C and a stream of gaseous ammonia was caused to pass through the mixture to saturation. The solid being obtained was washed with water after collection and crystalized from benzene. 7.55 g crystals m.p. l49-l52C were obtained.  
 Method b 2 g 2phenyl-2-oxo-ethanol and 1.4 g sodium cyanate were dissolved in ml anydrous benzene and then dropwise added with 2.1 ml trifluoroacetic acid. The reaction mixture was stirred for about 3 hours at room temperature. The mixture was then diluted with water. separating the organic layer and drying on MgSO The solvent was evaporated at a reduced pressure at 40 50C. The solidified residue was collected. washed with petroleum ether and crystalized from benzene. 1.950 g product m.p. l49-l52C was obtained.  
 EXAMPLE 2 4-phenyl-4-oxazolin-2-one (formula l.  
 Method A 2 g 2-phenyl-2-oxo-cthyl carbamate were dissolved in 15 ml 10% NaOH solution at room temperature. Upon cautious acidification of the solution, the product was separated. collected. washed with water and crystalized from benzene. l.7 g crystals m.p. l51-l53C was obtained.  
 Method B 5 g Z-phcnyl-Z-oxo-ethyl carbamate were refluxed for 5 hours in ml glacial acetic acid. After cooling. the reaction mixture was poured in a solution of Nag. CO and ice. The formed precipitate was collected and crystalized from benzene. 4.2 g crystals m.p. l5 l-l53C was obtained.  
 Method C 5 g 2-phenyl-2-oxo-ethyl carbamate and 100 mg p-toluensulphonic acid were refluxed for 5 hours in 50 ml toluene. using a reaction vessel permitting removal from the reactant mixture water formed during the reaction. Solvent was then evaporated at reduced pressure: the formed precipitate was collected and crystalized from benzene. 4 g product m.p. l5l-l53C were obtained.  
  By the general methods as described in the above Examples l and 2. the 2-aryl-2-oxo-ethyl carbam&#39;ates and 4-aryl-4-oxoazolin-Z-ones. respectively. according to the present invention were prepared. the following being a list for the features thereof:  
 l. Z-phhyl-Z-oxo-ethyl carbamate G Colourless crystals purified from benzene. m.p.  
 2. 2-(4&#39;-bromophenyl)-2-oxo-ethyl carbamate Colourless crystals purified from ethanol. m.p. l95l98C.  
 3. 2-(4&#39;-chlorophenyl)-2oxo-ethyl carbamate Colourless crystals purified from ethanol. m.p. l96-200C.  
 4. 2-(4&#39;-fluorophenyl)-2-oxo-ethyl carbamate (Formula 8, B F-Q Colourless crystals purified from benzene, m.p. l66-l68C.  
 5. 2&#39;(4&#39;-methylphenyl)-2-oxo-ethyl carbamate (Formula. 3, a n e-@- Colourless crystals purified from ethanol. m.p. l83-l85C.  
 6. 2-(2,5-dimethoxyphenyl)-2-oxo-ethyl carbamate (-Fomule. 3, R  
 (Formula 3, H.  
 (Formula 3, R  
  DDR5 (Formula 3, B a  
  OClg Colourless crystals purified from benzene. m.p. l40l42C.  
 7. Z-(diphenyl)-2-oxo-ethyl carbamate (Fommla 3, R BOG Colourless crystals purified from benzene. m.p. l80l83 C.  
 9. 2-(2&#39;-naphtyl)-2-oxo-ethyl carbamate (Formula. 3, H. l  
 Colourless crystals purified from benzene. m.p.  
 ll67C.  
 l0. 4-phenyl-4-oxazolin-2-one (Formula. 3, E  
  Colourless crystals purified from benzene, m.p. l5l-l53C.  
 l l. 4-(4&#39;-bromophenyl)-4-oxazolin-2-one (Formula 1, R w BQQ Colourless crystals purified from acetone. m.p. 248-250C.  
 (Formula. 1, R  
 l2. 4-(4-chlor0phenyll-4-oxazolin-2-one (Formula 1, I QmQ- Colourless crystals purified from ethanol. 260263C.  
 13. 4-(2&#39;chlorophenyl)-4-oxazolin-2-one (Female 1, n  
  Colourless crystals purified from ethanol. 207-2()9C.  
 l4, 4-(4&#39;-fluorophenyl)-4-oxazolin-2-one (Formula 1, a F- Colourless crystals purified from benzene m.p.  
 IMP-212C.  
 l5. 4-(4-methylphenyl)-4-oxazolin-2-one (Formula. 1, B 11 l7 4-diphenylyl-4-oxazolin-Z-one Colourless crystals purified from ethanol. m.p.  
  15 (Formal; 1, I (JG 35 Colourless crystals purified from benzene. m.p. 202-204C.  
 What we claim is: l. A compound of the formula:  
 Colourless crystals purified from ethyl acetate. m.p. 3Q  
 l6. 4-( 2,5&#39;-dimethoxyphenyl )-4-oxazolin-2-one (Formula 1, I. Q  
 Colourless crystals purified from ethanol.  
 wherein R is selected from the group consisting of:  
 2. Compound according to claim I wherein R is: