Thiazolino-pyrimidin-5-one derivatives, process for their preparation and applications thereof
United States Patent n91 Baetz THIAZOLINO-PYRIMIDlN-S-ONE DERIVATIVES, PROCESS FOR THEIR PREPARATION AND APPLICATIONS THEREOF [75] Inventor: Jacques Baetz, La  
 Garenne-Columbes. France [73] Assignee: Seperic, Morat (Canton dc Fribourg), Switzerland [22] Filed: Aug. 14, 1972 [2|] Appl. No.: 280,165  
 [30] Foreign Application Priority Data OTHER PUBLICATIONS Brown. ct al. J. Chem. Soc. l97l C, (8), 1527-8. Pashkurov. ct a]. C. A. 7|. l3088a l969). Matsunaga. et al. Yakugaku Zasshi 88(8). lO03-10l0 (1968). Abstract thereof.  
 [ 1 Apr. 8, 1975 Primary E.\&#39;aminerDonald G. Daus Assistant Examiner-Raymond V. Rush Attorney, Agent, or Firnw-Young &amp; Thompson [57] ABSTRACT Said derivatives are those of the general formula:  
  1 s N R Y I a N in which R,, R R and R are each hydrogen. an alkyl group or an aryl group, one at least of said symbols being other than hydrogen, or R and R form together a group (CH n being equal to 3. 4 or 5, and their acid addition salts. They are therapeutically useful. in particular as analgesic drugs.  
 7 Claims, 2 Drawing Figures THIAZOLINO-PYRIMIDIN-S-ONE DERIVATIVES, PROCESS FOR THEIR PREPARATION AND APPLICATIONS THEREOF This invention relates to a series of new chemical compounds endowed with therapeutic. particularly analgesic. properties.  
  These compounds (I) are those of the general formula illustrated in FIG. I of the accompanying drawing. in which R,. R R and R, are each hydrogen. an alkyl group or an aryl group. one at least of said symbols heing other than hydrogen. or else R and R form together a (CH- group. n being equal to 3. -l or 5. and their acid addition salts. particularly with pharmaceutically acceptable acids.  
  Thus. compounds (I) are 2- and/or B-substituted thiazolino-pyrimidin-S-ones. It should be noted that such substitutions may produce stereoisomers and the invention includes within its scope hoth the racemic forms and the optically active forms.  
  The alkyl and aryl groups that may he represented by symbols R, to R, are preferably lower alkyl and monocyclic aryl groups. respectively.  
  To prepare compounds (l). a process illustrated in H0. 2 of the accompanying drawing may he used.  
  This process comprises condensing a Z-iminothiazolidine (ll) in which R,. R R and R, have the above-defined meanings. with an alkyl alkoxymethylene malonate (Ill). in which R is a lower alkyl group. particularly an ethyl group. then hydrolyzing resulting ester (1V). decarboxylating acid (V) and then. if desired. salifying resulting compound (l).  
  lmino-thiazolidine (ll) may be used in free or salt form. In the latter case. the imine is released in situ by means of an alkaline compound. The condensation be tween imino-thiazolidine (II) and alkyl alkoxymethylene-malonate (III) is advantageously conducted within an organic solvent such as ethanol. Hydrolysis of ester (IV) is carried out in conventional manner. such as by refluxing in formic acid in the presence of methane-sulfonie acid. Decarhoxylation ofacid (Y) is also conducted in a known manner. such as by heating in the presence of copper oxide.  
  Intermediate compounds (IV) and (V) are themselves new compounds.  
  The following non-limiting examples illustrate the in vention.  
 EXAMPLE 1 Synthesis of 2.3-dihydro-3-methyl-thiazolo( 3.1a )pyrimidin-S-one (Formula (I): R, R R, H; R;, CH Code N&#34;: 77] l.  
  a. Preparation of ethyl 2.3-dihydro-3-methyl-5-oxothiazolo-(3.1a)pyrimidine-o-carhoxylate (formula (IV): R|:R- R;,=CH;;lR=C H,-,).  
  Into a 1 litre flask are added 58 g of 2-imino-4- methyl-thiazolidinc (Formula (II): R, R R, H; R,, CH;,). 108 g of ethyl ethoxy-methylene-malonate (formula (NH) and 500 ml of ethanol. The resulting pale yellow solution is refluxed during 4 hours. after which it is allowed to cool and is then placed over an ice-hath and is left overnight in the refrigerator. The material which has set to a mass is suction filtered. washed twice with ethyl ether and is then dried. to give 107 g of ester. m.p. l40-l42C.  
 Analysis: lotal nitrogen. (.ilculatcd ll ho:  
 Found 1 l .h7&#39;  
  h. Preparation of Z.3-dihydro 3-methyl-5-oxothiazolot 3.1al-pyrimidine-h-carboxylic acid (Formula (Y): R, R R, H; R =CH,,).  
  Into a 2 litre flask are added I00 g of the above ester. 77 g of methane-sulfonic acid and 800 ml of 907: for mic acid. This solution is refluxed during 4 hours. After cooling. it is poured into a 5 litre Erlenmeyer flask to which 3 litres of water are added. with stirring. Stirring is continued during a further hour. and the reaction mixture is then left in the refrigerator during 48 hours. It is then suction filtered. washed with ice-cold distilled water and dried in a vacuum oven at 50C. to give (1| g of acid. mp. l59l6(lC.  
 (alculatcd Found lilll&#39;i c. Preparation of ZJ-dihydroJ-methyl-thiarolot3.- 2a)pyrimidin-S-one on g of the above acid and l l g of copper oxide are intimately mixed in a 250 ml flask. and are then placed in an alloy bath at l7()C. When the mixture is completely melted. the temperature of the bath is brought up to 270C within l5 minutes. The reaction is complete within 5 minutes at 270C. After maintaining a further ten minutes at 27tl-280C. the reaction mixture is allowed to cool and is then taken up into 200 ml ofchloroform. treated with charcoal in the hot. filtered through hyflosupercel. washed four times with hot chloroform. after which the maximum amount of chloroform is removed using a rotary evaporator. The resulting hrown product is distilled at 24S250C and is then dissolved in ethanol. treated with charcoal. filtered. washed with ethanol and then left aside in the refrigerator during 2.5 hours. after which it is suction filtered. washed with ethanol and dried. to give 27 g of material m.p. 99 C.  
 Calculated Found Analysis: Total nitrogen:  
 Analysi Total nitrogen Calculated ow Found l lif&#39; I 3%: I 3.5%. ethanol lv EXAMPLE 2 Synthesis of I.3-dihydro-2mcthyl-thia2olo( 3.1a lpy rtmidin-ione (Formula (ll&#39;. R, I R, I R, I H; R;, I CH Code N&#34; till).  
  a. Preparation of ethyl Z.3-dihydro-2-methy1-5- oxo(3.2.a tpy rimidine-fw-earhoxylate (Formula (IV): R, I R,, I R, I H; R CH;,; R =C-1H5).  
  Z-lmino-5-methyLthiazolidine (Formula (ll )1 R, I R;, I R, H; R I CH HBr) 18 g) is dissol\ ed in ethanol (50 ml} \vhile \varming. When the solution is complete. 2.24N alcoholic potassium hydroxide (39ml) is added thereto. vvith stirring. during 30 minutes. The reaction mixture is then cooled and the resulting potassium bromide is filtered off. The ethanol solution is concentrated to 70 ml. Ethyl ethoxy-methyleneanalonate ml) is added thereto. and it is then refluxed during 2.5 hours. Crystallization occurs on cooling, The material is left aside overnight in the refrigerator and is then suc tion filtered. washed with ethyl ether and dried. to give lo g of product. m.p. I lZ9l30C.  
 Calculated Found Analysis Total nitrogen Analysis Total nitrogen Calculated U10;  
 Found llllht c. Preparation of 2.3-dihydro-Z-methyl-thiazolol3.- lal-pyrimidin-5-one.  
  From l l g of the above acid and 2.2 g of copper o. ide. using the procedure of Example I (c) to give 4 g of product. m.p l0ol07C.  
 Anaiysis. Total nitrogen. Calculated Found EXAMPLb 3 Synthesis of 1.3-dihydro-l-phenyl-thiavolm3.1a )pyrimidin-S-one (Formula (ll: R, I R, I R, I H. R I ll- (ode N&#34; 815 l a, Preparation of ethyl 2.3-dihydro-Lphenyl i-oxothiazolo-l 3.1a )pyrimidine-ocarboxy late (Formula (l\&#39;|: R, I R;, I R, I H; R: I C,,H R I C H J,  
  45 g of lintino 5-phenyl-thia7olidine hydrochloride (formula (lit 1 R, I R; I R, I H; R I C, ,H HCl) are suspended in ethanol (200 ml}. Alcoholic potassium hydroxide l00 ml. IN) is added thereto and the mix ture is stirred during 45 minutes. The resulting potassium chloride is suction filtered and washed with ethanol. 44 g of ethyl ethosy-methylene-malonate are added to the filtrate which is then refluxed during 2 hours and left overnight in the refrigerator. The mate rial is suction filtered. washed with ethanol and dried in an oven at 45C. lt is then recrystallized from ethanol. to give 47 g of ester. mp. I l20-l22C.  
 Calculated Found Analysis; Total nitrogen:  
  bv Preparation of Z.3-dihydro 2 phenyl-5-o tothiazolot 3.2.a]pyrimidine-o-carboxylic acid (Formula (V1: R, I R;, I R, I H&#39;. R: I C,,H  
  40 g ofthe above ester are dissolved in 550 ml of 90% formic acid and 16 g of methane sulfonic acid. The re sulting solution is refluxed during 4 hours. It is allowed to revert to room temperature. after which L500 ml of distilled water are added thereto. with stirring. Crystallization occurs. The reaction mixture is left overnight in the refrigerator after which it is suction filtered. washed with water, with ethanol and dried in an oven at C over potassium hydroxide. After recrystallization from ethanolatcetone. the resulting material is suction filtered. washed twice with ethanol and dried in an oven at 70C. to give 26 g of acid. mp. I l66l68(.  
 Calculated Found Analysis: l otal nitrogen.  
  0, Preparation of 2,3-dihydro2-phenyl-thiazolo(3.- latpyrimidin S-one,  
  20 g of the above acid and 3 g of copper oxide are in timately mixed in a 50 ml flask. Heating over an alloy bath is conducted as follows: the flask is placed at l30C; after 5 minutes. the temperature is at l50C; after 10 minutes: 200C. after l5 minutes: 240C; after 20 minutes. at the temperature of 260C. a substantial amount of gas is evolved; after 25 minutes. at 280C. heating is discontinued. The residue is taken up into 500 ml of chloroform. treated with carbon black and filtered The filtrate is brought to dry ness The resulting oil is distilled over the alloy bath at 250-2h0C The distillation temperature is 2 l0-2 14C. 12 g of product. mp I 99l0l( are collected.  
 vacuo. over an alloy bath at Elm-250C The distillate sets to a beige mass which is dissolved in 45 ml of boil- Anal vsis: Total nitrogen; Calculated lZ.lhi  
  Fmmd mg ethanol. On concentration in vacuo. the product crystallizes. after which it is left overnight in the retrigerator. suction filtered. washed with cold ethanol and dried in vacuo over potassium hydroxide. to give 5.3 g EXAMPLE 4 of product. m.p. I35C Synthesis of 511.6.7.8.9.9a-HeXahvdro LoitoAH pyrimidot 2. l .b l-hcnzothiazole lo (Formula llll R] R H. R: 1&#39;&#39; R;; I lCH- COtlC Anal \sis: Total nitrogen: (alculatcd 1345&#39; N&#34; 846) Found 13.25%  
 a+b. Preparation of 511.6.7.8.9.9a-hexahydro-4-oxo- -)l CidN&#34;855 Z-Amino-hexahvdro-benzothiazole hydrochloride l L t L l l 92g) prepared in known manner is dissolved in ethanol ml) and 0.5N alcoholic potassium hydroxide 19.5 ml) is added thereto. Potassium chloride precipitates out. and is then filtered and washed with alcohol. &#39;f&#34; 1&#34; left standing during 71 hours at 2sc. It is then dried the ttltrate and the resulting material refluxed during in vacuo at mom tempcrmum to g 9 g of p 3 hours. it is then brought to dryness in vacuo. &#39;lo the mp 02210400 resulting oil are added 25 ml of 90W formic acid and 2.175 g of methanesultonic acid. and the reaction mixl9.9 g of racemate N&#34; 77l obtained according to example l are dissolved in I ml of lukewarm ethanol. Pure crystalline L(+)-tartaric acid (169 g) is then added thereto portionwise. The resulting solution is fil tered and washed with ethanol. lt is then cooled and ture is refluxed during two hours. It is then brought to dryness in vacuo. and a 2.55? aqueous sodium acetate solution ml) is then added thereto. The precipitate 3 Anahsis: Total nitrogen: Calculated 16.65% Found lbtili is filtered off. washed with water and dried in vacuo. to give 1.98 g of product. m.p. l8ll82C. lal 2.2 (c 4.3%. methanol).  
  The constitution and physical properties of compounds (I) obtained according to the examples described above and of other compounds (I) prepared in a similar manner are summarized in the following Ta ble. In this Table are also reported data relating to the 4 analgesic activity of compounds (I). as determined by bne of the conventional testing procedures for this activity. the writhing test.&#34;  
 Mice are given a single intraperitoneal injection of 0.1 ml of 0.6% acetic acid. The compound (ll to be tested is administered orally at a dosage from I to 20 Anal sis: Total nitrogen Calculated l l.l01 Found l 1.02;  
  c. Preparation of5a.6.7.8.9.9a-Hexahvdro-4-oxo- 4 pyrimido (2. l .b )benzothiazole Into a flask is added a mixture of 8.9 g of the above carbox vlic acid and 1.4 g cupric oxide. Theflask is imi i 4 1 i e 4 i mersgcd bath 2&#39; 9 f tempu mg/kg. one halt-hour prior to acetic acid IDJCCUOD. The lure brought P m 240 C w&#39;thm 5 Z mmuies&#39; number of characteristic writhing movements induced O i barhoxylmmn hegms about 240 and the by pain is counted during the IS mtnutes which tollow action mixture is maintained during 5 minutes between the acetic Mid injection 260 and 290C. after which it is cooled. The residue The magnitude of the action of each compound deis taken up into 50 ml of chloroform. filtered over clarscribed is expressed using front one to four +s. four +s cel and washed with chloroform. It is then distilled in representing maximum activity.  
  I1 d-camphorsulfonic salt of derivatn e n 771 The analgesic activity of compounds (It makes their application in human medicine possible. said compounds being administrable b the oral. parenteral or rectal route at a dail dosage regimen getter-all comprised between lllll mg and )(lll mg.  
  For such administration. compounds (I) are formulated as therapeutic compositions. with the \ehicles or escipients suitable for these various routes of administration.  
  The compositions in unit dosage form. such as tablets. suppositories and ampoules contain preferably from 100 mg to 300 mg of compound (I).  
  Hzoing now described my invention. what I claim as new and desire to secure by Letters Patent is:  
  l. Thiarolino-pyrimidin--one derivative selected from those ha\ing the formula Ill Jll  
 in which R and R are each selected from hydrogen. lower alkyl and phenyl. and R and R are each selected: (a) front hydrogen. lower alkyl and monocyclic aryl and (b) from radicals such that they form together a group (CH- n being selected from 3. 4 and 5. one at least of substituents R,. R R and R being other than hydrogen. and a pharmaceutically acceptable acid addition salt thereof.  
  2. 2.3-Dihydro-3methyl-thiazolo(3.2.a]-pyrimidin- S-one and its pharmaceutically acceptable acid addition salts.  
  3. ()-2.3Dihydro-3-methyl thiuzolo(3.2.ajpyrimidin-S-one and its pharmaceutically acceptable acid addition salts.  
  4. 2.3-Dihydro-3-methyl thiazolot3.2.a)pyrimidin- S-one d-camphorsulfonate.  
  5. 2.3-Dihydro2-methyl-thiaz0lo(3.2.a)pyrimidin- S-one and its pharmaceutically acceptable acid addition salts.  
  6. Z .3-Dihydro-3-ethyl-thiaz0lo( 3.2 .a )pyrimidin- S-one and its pharmaceutically acceptable acid addition salts.  
  7. 511.6.7.8.9.9a-Hexahydro-4-oxo- 4H pyrimidotl.l.h)-benzothiazole and its pharmaceutically acceptable acid addition salts.