CA1053239A - Imidazo (2,1-b) thiazoles - Google Patents

Abstract

ABSTRACT

There are disclosed certain novel imidazo (2,1-b) thiazoles, their physiologically acceptable acid addition - or quaternary ammonium salts and a process for their preparation.
Said compounds show a good anti-diabetic activity and have the formula

Description

iOS3Z39 -1-The present invention relates to new imidazo(2,1-b) thiazoles, processes for their preparation and pharma-ceutical compositions containing said compounds.
Several orally administrable hypoglycaemic drugs are known which belong mainly to the following chemical groups:
1) Arylsulfonylurea derivatives. This group comprises well known drugs, e.g. Tolbutamide, Chlorpropamide, Diben-clamide, Acetoxamide and Tolazamide.
~ Biguanide derivatives, e.g. Phenformin The arylsulfonylureas reduce the fasting blood sugar level of intact or glucose loaded animals, but they do not act in this manner in animals made severly diabetic with alloxane. In human beings the arylsulphonylrueas are effective only in individuals who have a pancreatic reserve of insuline as in non-diabetics or mild diabetics whose illness started in adult life, requiring a daily insuline dosage below 10 units. However, these compounds do not act in patients with severe diabetes and in cases of juvenile or growth onset type of diabetes. Moreover, they cannot be used in patients with a tendency to ketosis or ketoacidosis. They may cause severe hypoglycaemia, with the acute neurologic picture of hemiparesis and coma. These compounds do not possess a direct insuline-like activity.
Phenformin and certain other biguanides are more effective than the arylsulfonylurea as they produce hypo-glycaemia also in pancreatectomized or in severe alloxane-induced diabetes. The optimal decreasing of blood glucose concentration ~Q mean = 135~, is achieved with Phenformin .. . . ~ . ... .

~OS~Z39 -2-in animals with a starting blood glucose concentration of 250-300 mg/100 ml. However, some activity (~mean = 90) is still achieved at a starting concentration up to 380 mg~l00 ml. However, the therapeutic dose of Phenformin is close to the toxic one in human beings and may produce anorexia, nausea, vomiting, and later weakness, lethargy and weight losses.
The Phenformin combined with insuline may make a labile diabetic patient more stable and this is one of the main clinical applications. Other applications are in cases of maturity onset diabetes accompanied by obesity or primary and secondary aryl sulfonylureas failures.
There was therefore the need for a new, non-toxic anti-diabetic drug, with an insuline-like mechanism of action, acting orally on the most severe diabetes as for example the juvenile or growth onset type of diabetes.
It has now surprisingly been found that certain imidazo (2,1-b) thiazoles achieve improved properties over the known drugs.
Some of the compounds according to the present invention have a mean, statistic antihyperglycaemic activity which is stronger than that of Phenformin and they are particularly effective in the treatment of severe diabetes on rats. When the starting blood glucose concentration is higher than 380 mg/100 ml the ~ can reach a mean value of more than 230 with a % of 55~.

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~0 5 3Z 39 - 3 ~

In ~qu~l condition~ th~ me~ Q and~ ~ of thc Phenformin sre r~pectively 50 and 10%- ~he lasting time o~
a~ti~ity is longer than thAt o~ Phenformin (5 houre)~ ~
and it is still a~tive srter 24 hours. No gly~osuria~- -antidiuretic or other activitie~ are present as unde~
rable or toxio eide ef~eot~. Th~ hypoglycaemic efiect o~ the ne~ imidazo (2~1-b)th~azoles derl~atl~ on norm~l bei~s is~ as with PheD$ormln~ ~ery low~ ~ 20%) thus preventing a po~ib~e bgpoglyca~mic coma.
The pre~ent ~nvention thue consi~ts in imidazo-(2~1-b~
thlazoles o~ general ~ormula I :
B ~ --7-,1 - a A ~ D
\ //\ / -N' S :,:" ,.. .
~h~rein at leas.t ona o~ the ~ubstituents A, B, C and D ~ -.
sta~ds for one o~ the ~ollowing raaioals: (CH2)n COOR, H2)~CON ~ , (¢H2~nCN~ (C~2)n a~3, (¢N2~n CH

(a~z~ cH2oaoRl~ (OH~2~n CORl, in whichs an inte8er of:O - 2~ -: R ~t~nts for a(~tr~:ght or branched) alkyl, aryl :ar~l~yl~or~ yclio radioal,~ior~ hydrogen atom, or:`an~norg~nio oation e.g. ~odium and calcium or ~or ~ -a~ion:~ E ~ :in which E, E' and E~ msy ~tand for hgd~gen or Sor the ~ame~ or different hydroxgalkyl, alkyl, alkyl~mi~o ~optionall~ cub~tI~tuted)~ alkylcarbalkoxy or alkylo~rbo~y rad1oal, " , - : . :.

., . . . . , .: -,:
., ,,:, : - ., . .: -lS~5;~Z3g the N C group standing for an unsubstituted or substituted amine, cyclic amine or a hydroxylamine or hydrazine group;
X stands for a halogen atom, or for a hydroxy, mercapto, alkoxy, aryloxy or aralkoxy radical, or for a N C group;
Rl stands for (straight or branched) alkyl, aryl, aralkyl or heterocyclic radical;
substituents A, B, C and D not standing for ~ :
one of the above groups standing for a hydrogen atom or for a (straight or branched) alkyl, aryl, aralkyl or heterocyclic radical;
C and D together with the bond connecting them may stand for a cycloaliphatic radical;
the dotted line standing either for two hydrogen atoms or for a C=C bond;
or one of the physiologically acceptable acid addition - or quaternary ammonium salts; excluding:
a. 2-Carbomethyl-3,5,-dimethyl-6-carboethoxy-imidazo(2,1-b)thiazole; and b. 3,5-dimethy].-6-carboethoxy-imidazo(2,1-b)thiazole.
Preferred compounds of general formula I are compounds of general fo~la Ia \N ~ \ S /

in which A' stands for COOR", R" standing for a hydrogen atom for a hydroxyalkylammonium or an inorganic cation or for a lower alkyl group; or for CH20COR"', R"' standing for an alkyl group or for an optionally substituted phenyl group;

:~ .
.

~)S:~239 C' ~tand~ for methyl~ tert. butyl or a~ optio~ally eubetituted phenyl group~ a~d D' atsnd0 for hydrogen or an alkyl group.
~ he alkyl radical hae advantageou~ly 1-8 oarbon stom~, th~ aryl radical ia praferably a subetituted or u~eub~tituted phenyl~ diphcnyl or ~apkthyl radioal.
The heterocyclic rsdi~al i~ preferably aelocted amon~
the 3ub~tituted or unsubstituted imidazolyl~ pyridyl~
thienyl, or ~uryl radicsls.
As ouitsble a~ids for the prepsratiQn of the aaid additio~ aalt~ thexe ~hould b~ me~tioned the hydrochloric~
hydrobromi¢~ n1tric~ ~ulfuri~ and pho3phoric acid.
~oreo~er~ also certain organic aoide may be utilieed.
Ae preferable ~ter~ for the pr6paration o~ th~ quaternary ammonium salt~ there may be mentioned eater~ of ~ulphuric, hydro¢hlori~ hydrobromic and of oertain eromatic ~ulfuric a~ida.
!~he abo~e two excluded compounds have been de~cribed by Ochiai~ Ber. 69, 1650 (1936~. However~ no pharmaceutical aetiYity ha~ ~o ~ar bse~ reported for aame.
~ hc oompou~de o~ ge~er~l formula I can be prepared by ~riou~ prooe~fla.

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- : .. .... ~ : :
.,' ~. ,- ~ ~ ' ' : ' , .

lOS;~Z39 - 6-On~ proee~ for the prepara~ion of oompound~ of genorsl f o~muls I cQnelst~ in the condenaation of a ~-h~loo~rbonyl derivative of gen~r~l formula II
o~ a- c ::
Y - CH - D
hiGh G and D hav~ the 8ame meani~g as aboY~, Y ~t~ndE~
$or e, halo6a~ e.tom s~d the oarborlyl group m~y be proteeted r~adily ~lea~red group; with 6 2-mer~aptoimidBZole do~ ti~o oi ge~ral fo~mula III
B- ~ NH
~TI ! s~ ~
\N~ .
h ~ and B ha~e th~ 8ame meaning as above to yield a thioo~r~o~rl derivative o~ general formula IV
B - ._N~I O 8 . - C
A ~ D
; \ N/~ S
A~ B~ C and D ha~e tho o~me me~ g as above and~
bhe o~rbonyl oompou~d o~ the haloe6rbon~1 d~rivati~e Or gener~al formula II W8Q proteoted~ subjecting the . . .
~olqpou~d obtsi~d to an ~idic ~leavage reaotion; asid hlo~arbon~l deriy6~ti~e of ~e~eral formula IV bein~ :
03~rt~d:~to the ~ompound o~ general ~ormula I with e, uitable rea~ent by 4ye}i~Rtio~ and dehydratation by , .
.metb~oa~ k~own~p~r a~
-.oo~d~at10n re~tion between the 30mpou~ds of on~al ~o~u1E- II arld III i~ prererably perforDI~d in :a -uit~ble inert 801~rent~, A8 suitablo eol~ent~ there .:m~3r~e merltioned, ~or example, al~ohols~ e~g, meth~nol, -:
e~ ol~ i~op~opa~ol~ buta2lol~ or aprotio ~olvent~

1~)53Z39 ~ 7_ eOg. acetonitrile, dimethylformamide (DMF)~ dim~thyl~
~ulfoxide (DMS0)~ et4.
The conden9ation raaction i~ p~rformed at tempera~
tur6~, whi¢h ~ar~ betw~e~ room temperature and the boi~
lin~ temp~ratur~ o~ the ~olYentO
~ he r~sctlon can be per~ormed i~ any ~ultable medium~
i0eO~ in an al~alins, neutral or ac~dio medium~ In ca~e ~hat the reaction i~ performed in ~n ~lkaline medium a met~l hydrida or an alkoxide are u~ed and the .~main reaotio~ produ~t ia the thiocarbonyl derivative of general iormula IV. Wh~n the rea¢tion ie performed in a ~e~ral medium at room temperature~ the m~in re~ction produ~t i9 the ~orrespondlng hydrohalide ealt o~ the :~
thio¢arbonyl derivativa of general formul~ IV. However, ln c~e that said Go~deneation rea~tion ie performed in a ~eutral mediwm at elevated temperature3~ eOgo 80-190C, the ri~g alo~ure and the dehgdratation of the thiocar-bo~gl deri~tive of ~e~eral ~ormula IV is dir~Gtly psrformed .a~d the desired sompou~d o~ genersl ~ormuls I i8 obtained.
The thiooarbo~gl deri~ati~e ef general formul~ IV
~6, as ~tated abo~e, not alwag~ i~ol~ted. In 80m~ in8tanGe~
tha final compound o~ gen~r~l formula I i~ directly o~tÆined~ Somet~me~ th~ rinB i~ ~lo~ed but tho dehy-dratat~o~ reaction ha~ to b~ per~oxmed. In c ase that a~
interm~d~st~ compou~d i8 i~olat~d the ring ¢losure and/or t~e dobydrats~io~ reaation ~an be performed by variou~
thod~. Er ~ pr~$erred ~thod the bas~ of s~id ~hio-oarbonyl d~ri~a~iYe of goneral formu}a ~V or the hydroxy dihydro th~azol~ der~atiY~ ~ re~luxed in phosphorus oxy~hlor1de or suIfuria ncid~ Another method con~ist~ ~n r-flu~ing a hydrohalio ~alt o~ ~aid thiocarbonyl derivative i8 a euit~blo inert ~olvent~ eOg- butanolO

1053Z39 - ~ ~
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The rcaotio~ time of the rin~ 0108~re and dehydra-tation proce30 may ~ary to B large éxtent, iOe.~ between 10 minutea up to 24 hour~ according to the ~ub~tituents ~nd the re~tion oonditione.
~ h~ thiocarbonyl deri~ative~ Or ~eneral formula IV
with the e~ception o~ 2-thioacetongl-4t5)-csrboeth ~(4)-methylimidazole are ~ew compounde. The present inYêntion thus embraces also said ~ew oompounde.
~ nother proce~s $or the preparation of compound~
o~ goneral ~o~m~la I consiets in the conden~ation of an ~-halocarbonyl derivative of general ~or~ula V
O ~ ¢ ~
Y - a~ - B
in whioh A ~nd B have the same meaning ae sbove and Y
~tands for 8 halogen atom; with a 2-amino-thiazole derivative of general ~ormula VI
- , ..
D ~ NH

n whlch C and:D ha~e the same meaning as abo~e.
S8id acndensation reaction ia pre~erably perfoxmed ln a~su1t:abl- in~ert eol~ent, ~or eX8mple~ oertain~alaohol~
protia solvent~ e.g. methanol, ethanol~ acetonitrile~
, , ~
D~F,~DUSO,~.eta.~The.reaction temperature ~ar1es from :~
o soa. ~The reaotion tlme ~rie~ between ~ome minutes and~some days~acoording~to the substituents and the r-aet10n sond1~10n~.
Mo~t or:;the~aompounds Or genoral:~ormula II, III, V
d VI,~ ~re.~own..Tho~e whiah. are.new ones can easily be pr~p~r-d~by method~ sn~logou~ to tho~e by wbich the kn~wn~oom~ ~ 8 ~re prepared.

105;~Z~39 The variou~ 0ub~t~tu~nts in the compound~ of Kener~l $ormul~ I may be introduc0d ~ithHr dire~tly in th~ courae of one of the abo~ proce~e~ or by w~y of ¢on~ertin~ o~e compound o~ ~eneral formula I into another one by method~
k~ow~ per ~e~
Thu~)~or exampl~, the COOR~ CF3, end COR' r~dic~l~
c~ be i~trodu~ed i~ the coura~ o~ the oo~densatio~
reactlo~ The CH ~, C~20COR', CN and CO~ ~ubsti~uentc aro better introduced by tran~form~tion of the c~rbalkoxy iunotio~, e.&. by reductlon to hydroxymethyl~ halo~enatlo~ -to chloromethgl and amlnoly~is Or ~eme ~ith A primary, o~ondary or cyclic amine (X ~ 0~, Cl, N~ , re~pectlvely);
~6teriilcstion with a ~uitable a¢id ohloride of tha hydro~y ~ : ~
methyl functlon (~ ~ CH20CORl). 'l'ho ro~ction of the ~ -~hloromethyl derivatiY~s with a ~uit~blo metal slko~ide or phenats ylelds t~e do~ir~d ether (X ~ CH20R)~ l'he ~mide :~ :
Kroup ~X ~ CON~ ~ can be obt~ln~d di~ect~y fro= the :~
o~t~r or ~ia the aold ohlorid~ ~nd ~rom the amlde the cy~no ~roup oan be o~tai~ed~
The~ compound~ Or ge~eral ~ormula I, whorein the dott~d llno stand~ for 2 hydrog~n atam~ can be prepared by rsducing a thio~arbonyl deri~atlva o~ general formula IV with oodlum borhydrlde to yield a ~-thioalcohol of go~ral Sormul~ V~
B - ~ :NH ~0 ~ CH - C ~::
A ~ D
\ N ~ \ S / ~ ~ :
whioh A, B, C ~d D ha~o th~ ~ame m~a~ing aa abo~e and cyoll~atio~ and dehydratation of 8amg dlrectly or a*tor eateri~i~ation.

~ -.: . , ''' ' ~ :- . : ' ~' -, - , i. . - ~, - . ~ .
.,, ~ . ~ , .

l.oS3'~39 The ~-thioalcohols of general formula I and their esters are new compounds The present invention embraces also said new compounds.
Those compounds of general formula I in which at least one of the substituents A, B, C and D stands for 5CH2)n COOR in which R stands for an inorganic cation e.g. sodium and calcium or for an ion E' - NH in E
which E, E' and E" may stand for hydrogen or for the same or different hydroxyalkyl, alkyl, alkylamino (optionally substituted), alkylcarbalkoxy or alkylcarboxy radical; are prepared by dissolving the corresponding imidazo-(2,1-b) thiazole carboxylic acid in an inert solvent and adding to the solution obtained a solution of the appropriate base.
- As suitable solvents there may be mentioned, for example, ethanol, acetonitrile, etc.
The acid addition salts of the compounds of general formula I are obtained by methods known per se, e. g. by dissolving the base in a suitable solvent (e.g. alcohols, ethyl acetate, acetonitrile, etc.) and thereafter adding the selected acid at a temperature of O - 80 until the pH is 1-5.
The quaternary ammonium salts of the compounds of general formula I can also be prepared by methods known per se, for example, by reacting the base with a suitable ester of the desired acid, e.g. butyl bromide, methyl sulphate, methyl p-toluensulphonate, etc. in or without a suitable solvent.
The present invention consists also in pharmaceutical compositions containing as active substance an imidazo (2,1-b~ thiazole of general formula I. The new compositions are preferably administered per os. However, if desired, .

- 10~3239 they may be administered in any other suitable form, e.g.
as injection, suppositorium, etc.
The new compositions according to the present invention are thus advantageously prescribed in the form of tablets, pellets, capsules, ampoules, powders, granules, solutions, suspensions, emulsions, injections, suppositoriums, etc. Said compositions are prepared in a conventional manner, i.e., by the addition of suitable binders, extenders, carriers, fillers, solvents, emulsifiers, other suitable therapeutic compounds, etc. -Naturally said compositions should comprise thera-peutical effectful doses of the new compound according to the present invention. Said doses may vary, however one may consider as effectful antidiabetic does, daily doses from 10 mg up to 3 g of the new compound according to the present invention. Said doses vary according to -the compound utilised, to the severeness of the illness, whether the drug is to be administered to a child or to a grown up person and in which manner it is administered.
The present invention consists also in a method for the reduction of the blood sugar level in patients suf-fering from diabetes in which a composition comprising a therapeutical effective dose of a compound according to general formula I is administered.
The present invention will now be illustrated with reference to the following Examples without being limited by them. All temperatures are given in degrees Centrigrade.
All melting points are uncorrected. The solvents indicated in brackets after the melting points are those from which the substances are recrystallised.

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`` ll)s3239 Example 1 158 g of 2-mercapto-4(5)-carbomethoxy imidaæole, [(prepared as described in JACS 71, 644-647 (1949~], are suspended in 1.5 1 of dry methanol containing 1 M
sodium methoxide and 169 g of bromoacetaldehyde dimethyl acetale are then slowly added to said suspension. ~fter refluxing the suspension for 16 hours, 1.5 1 of benzene are added thereto and the methanol is evaporated. 2-[4(5)-carbomethoxy imidazolyl] thioacetaldehyde dimethyl acetal precipitates; after extraction with isopropanol of the precipitate and evaporation of the solvent 228 g of substance are obtained. Said substance is dissolved in 1.2 1 of a 15% aqueous HCl solution and after agitation for 2 hours at room temperature sodium bicarbonate is added until the pH is 7.5. The precipitate obtained is filtered off to yield 149 g of 3-hydroxy-6-carbomethoxy imidazo (2,1-b)-2,3-dihydro thiazole.
The above substance is refluxed for 2 hours in 1.4 1 of phosphorus oxychloride. The solvent is distilled off under vacuum; water and chloroform are then added to the residue and sodium bicarbonate is added until pH 7.5 is obtained. The chloroform layer is washed with water and the water phase is extracted with chloroform. The dried chloroform solution is evaporated and the residue i8 crystallised to yield 84 g of 6-carbomethoxy-imidazo-~2,1-b)thiazole; m.p. 153-156, (Abs. ethanol).
Example 2 The 6 carbomethoxy imidazo (2,1-b)thiazole prepared as described in Example 1 and à solution of isopropanol containing dry HCl is added until pH2 is obtained after dissolution of the substance. The solvent is evaporated and the residue being 6-carbomethoxy-imidazo-(2,1-b) thiazol~ HCl i~ cry~tallieed from ab~olute slcohQl;
m.pO 182-185.
E~m~le 3 A ~olutio~ of 15 g of 2-aminothiazole and 31.4 of ethyllbromo aoetoaoetate in 200 ml of acetonitrile is stirred for 2 hour~ at room temperature. After refluzlng the ~olution for 3 hour~ ~t i~ decolori~ed and the -sol~ent i~ ev~porated under ~aouum. Tho.re~idue obtained ie dlseol~ed 1~ wster~ then neutrslieed with sodium bioarbonste ~nd eztraoted with ohloroform. ~he ~ol~ent i~ dried and evaporated. The reeidue is the~ diesol~ed :
in aoetone and ¢oneentratod nitria acid ie.then dropped into the ~olution until p~ 4,5 le obtai~ed~ 32 g of ethyl imidazo (2,1-b) thiazole-6-aoetato nitrate erletalli~ea; ~ -m,p. 102 - 106 ~aeeto~e~.
E~m~l~ 4 A eolutlon o~ 4,25 g Or ~thgl-~midazo-~2~1-b)thiazole-~-~aetat~ ba~e ~obtainod from the nitrate ealt prepsred a~d-s~r1b-d i~ B~a~ple 3) and 8 g Or b ~1wm hgdroside ~
oo~h~dr~t- in aoo ~l Or water i~ re~lu~ed ~or 2 hour~
8ul~urio aoid 18 then droppod into the ~olution until total.jreo1p1t~t1o~ or barium sulphst~ 1~ obtained a~d ~.
o e~oe0~ Or S04 io~o iB pre~o~t, APt~er;filterlng the preolpit~te off~ the solution 10~:~-oh-a ~1th;~oh~oroform~ a~d ¢o~oentrated to 1/4 Or the iti~l ~oIume to g1old 3~2 g o~ imid~zo-~2,1-b)thia201e- .:
6~aoot1o aoId; -,p.~193~- 195.

~, , ~ . , , - - .. ~.. , , ~ ,, ; . . : , .

1053Z35~

~, A ~olutio~ of 15 g of 2 ~minothia~ole and 40,65 g o~ ethyl- ~ -bromo benzoyl acetate in 120 ml of ab~olute ethanol i~ ~eflux~d for 12 hours. The ~ol~ent i~ e~apo-rated and the re~iduo i~ recri~talli~ed from i~oprop~nol to yield 9 g of 5-carbosthoxy-6~phenyl imidazo(2,1-b) thia$ole hydrobromide; m.p. 198 - 200o The mother liquor iB evaporated and the re~idue iH dis~olved in ohloreform. After washln~ with alkaline water a~d drying, ~h~ ~olvent i~ e~pQrated and the residue ie dis~olved in ether. A ~olutio~ of dry HCl in ieoprop~nol i~
added u~til the pH i~ 3 to yield 10~2 ~ of 5-carboetho~y-6-phenyl~imida~o~(2,1-b) thiazole hydrochloride; mOpO175-178 ~b~.ethanol).
Æ~ample 6 18.6 g of 2-mercapto-4(5)-carboetho~y-5(4)-methyl imidazole(obtained by nitroYation of ethyl a~etoa~etate~
redu~tion of the oxymino deri~ativ~ to ~thyl -c~-amino acetoacetate ~nd oycli3ation with potae~ium thiooyanate) sre ~tirred at roo~ temp~ratur~ in a eolution of 2.3 g of sodium in 150 ml of abs~ ethanol, 19.7 g of a-bromo~
acetald~hgd~ diethyl a¢et~l ~re added to the ~oh~ion ~nd the su~p~n0ion obtained i8 r~fluxed ~or 12 hour Aft~r ~ooling the precipitated ~odium bromide i9 filtered off and the filtrate i9 e~aporated. 28.7 g of 2-/~(5)-carboethoxy-5(4)- methyl ~i da~olyl7~thioacetaldehyde diethyl aoetal aro obtained a3 an oil. The oil is dissolved in 150 ml of n lSUh ~olutio~ of hyd~ochlori¢ acid and the aolution i~ then ~tirred ~or 1 hour ~t room temperatureO
Aft~r ~eutralisatiOn with sOdium bi~arbo~at~ 3-hydro2y- ;
5-methyl-6-~ar~ethoxy-imida~0-(2~1-b)~,3-dihydrothiazole, preuipitate~ and i4 ~ilterel off; m.p. 123-124~ethyl a~etate)0 ' ' '- `' '' 13 g of the ~bove compound are reflu~ed in 130 ml of phosphorus oxychloride; after v~cuum evaporstion of the solv0nt the residue i8 dia~ol~ed in i¢e-water, neutralised with Hodium carbo~ate to yield, after filtrstion, 7 g of 5-methg1-6-carboethoxy-imidazo-(2,1-b)thiazol~;
m.p. 102 - 103 (hexane).
Ex~mPle 7 a. The same reaction as de~cribed by Ochiai/~er.69,1650 (1936~7is perYormed, i.e., 2-mercapto-4(5)-carboethoxy-5(4)-methyl lmidazolo iB reacted with chloroacetone at room temperature~ to yield 2-thioacetony1-4(5)-carboetho~y-5~ methylimidszole. Said ~mids~ole derivative i~ reactod ~ith phoephorus oxychloride to yi~ld 3,5-dimethy1-6-csr~ootho~y-imidazo-(2,1-b) thiazol~; m.p. 141-142.
b. A ~olutio~ of 11.4 g of 2-amino-~-methyl thiazole and 21 ~ of ~thyl ~ -bromo ethylglyoxslate in 200 ml o~
BCetOllltri10 i8 reflu~-d for 5 hours in a nitrogen atmo~phere ~nd 18 then allowed to ~tand ~or o~e night at room tempera-ture. After deoo~ri~ation snd~ovaporation of the solvent~
~ - . .
tho reèiduo i~ dissolvad in water and the solution obtainod ~ ;
i8 neutrali0ed ~ith sodium ~arbonate. 16 g of 3,5-dimethyl-6~oar~oetho~y idszo-(2~1-b)thiazole precipitate Qnd aro llt-r d off; m.p. 141-142(ethyl aoetate)~
E~QmD-~e 8 solution of 15.8 g of 2-mercapto-4(5)-~arbometho~y- -lmida~ole and 10.17 g of chloraoetone in 80 ml of ab~.ethanol reSlux-d for 20 hours~ Th- solution i9 then oooled and -~
ether ie added to yiold, after filtration, 16 g of 3-methyl~
6-carbo-etho~y-imid~zo-~2,1-b~thla~ol~; ~.p. 169-174(~cetic aoit).
~, - .l.~ ~
l()S3Z39 A solution o~ 1508 ~ 0~ 2-mercapto-4(5~ carbomethoxy-imidazole a~d 10017 ~ of chloroacetone in 100 ml of aba.
ethanol i~ refluxed for 2~ hour~ in a nitroge~ atmosphere.
~he ~olution i~ co~centrated snd then ether i~ ~dded to yield 25 g of 4(5~-oarbomethoxy-2-acetQ~ylthio imidazole hydrochloride. Tho baa~ hav~ng a m.p~ 10605-10705~
obtsined from the hydro¢hloride i8 reflu~ed in 125 ml of POC13 for 2 hour~O '~he ~olution la then concentrated under ~aeuum and ice-water i~ sdded to the residue.
After neutr6~1isatio~ with Dodium bicarbonate the a~u~ou~
oolution io extractad with chloro~orm. Tha aolvent i~
the~ evaporated to y~ld 17 g of ~-meth~ 6-c~rbometho~
i dazo-(2,1-b)thiszole; m~pO 170-173(i~opropanol)O ~ .
Exam~lo 9 5 g o~ 3-methyl-6-~arbomethoxy-imidszo-(2~1-b)thi~zole ~tain~d a~ de~cribed in Example 8, ~re di~olved with ~:
stirrill~ at room temperaturo i~ 100 ml o~ acetonitrile containing 10 ~1 of methyl iodide. ~fter Z4 hour~ 3 g of 3-methyl-6-~rbomethox~-imid~zo-(2,1-b)thi~zolium methyl iodido cry~t~ e and ~re ~iltered off.
~ he f iltr~t~ i8 then o~raporated and the residue i8 di~aol~ed i~L wat~r and the aqueous Eo~tion obtai~ned i~ e~tracted with chloroform- The water ~.~ di~tilled off under Yacuum and the re~iduo obtained i8 continuously e~tracted ~ith ahloro~orm. A~ter conoentratio~ eth~r i~ -added to yiold additional 205 g of~the above quaternary ~lt, m.p. 179-~82 (dec.).
Example 10 100 B o~ 3-methyl-6-carbomethoxy-imidazo-(2,1-b)thiazole (obtain~d a8 de~ribed ~n Example 8) are re~luxed ~or 2 hours ~a 500 ml o~ a~ a~u~5 sol~it.~on of 1~% NaO~. Acetic acid - ~ . .
.r, . ' ~ ' :

~S3Z39 - :L7 i~ th~n dxopped into the aolution until the pH iE 5.
The s41ution i~ then cooled to yi~ld, sfter filtratio~, 7~ ~ o~ 3 -methyl-imid zo-(291-b)thiazole-6-c~rboxylic acid; m~p~ 245-247.
EY~m~le 11 1 g of 3-methyl-im-~dazo-~2~1-b)thia~ole-6-c~rbo~ylic acid obt~ined a~ described in Exa~ple 10 are reflu~ed ~n 10 ml of ethanol ~nd a eolutio~ of 0~57 g o~ 2 ami~o- ~

2 (hydroxymethy1)-1~3 propanediol in 10 ml of ethanol ~ . -ie add~d. After coolin~ ie 1,5 g of 2'~(bydro~ymethyl)~
1~3l prop~nediol-2'-smmonium 3-methyl imid~zo(2,1-b) : ~:
thiazo~ 6-carboxylat~ precipitatedt which were ~iltered o~; ~.p~ 196-197.
~am~l 12 1 g of 3-methyl-imida~o-(2,1-b)thiazole-6-oarboxyli~
3cid obtained a~ deecribed in ~x~mple 10 are re~lu~ed in 10 ml of.ethanol a~d a ~olution of 0,49 g of 2-smino-2 methyl-l-propa~ol i~ 5 ml o~ ethanol i8 added. After ~
oooling l g o~ 2'-~ethyl l~-propsnol 2'-ammo~ium 3-methyl- : :
tmldazu-(2tl-b)thiazOle-6-C~rbO~ylate pre¢ipitated a~d ~:
wer~ ~iltered off; m.p~ 235-23B. :~
E~am~le 13 -1 g oi 3-methyl-imida~o-(291-b)thiAzole-6-carboxyli¢ .
~id obta~ned a~ d~cribed ~ Example 10 are reîlwced in 25 ml o~ ethanol ~d a ~olutio~ of O . 55 g Q~ triethyl-e. ir~ 5 ml o~ ethanol iB added. Ether i~ added to the cooled ~lutio~ til ~ oi}y l~rer app~ars~ The solYent i8 the~ ovaporatod to yield 1~4 ~ of oily triethy.l_~mmonium-

3-mothyl-imida~o-(2,1-b)thiszole-6-~arbo~rlate.

- . . ~ ~ .

.

_ 18 Ex~mDl~ 14 1 g of 3-methyl-imida~o-(2,1-b)thia~ole-6-carboxyliG
a~id obtal~ed a~ de~cribed i~ Example 10 ~re r~fluxed ln 25 ml of ethanol ~nd a aolution o~ 0056 g of dimethyl-am$nopropylamin~ in 2 ml of eth~ol 1~ added. ~he sol~nt iB then evaporated to yi~ld 1.5 g 9f oily~ ~ater-eoluble 3~-dlmethylaminopropyl~ ammonium 3-m~thyl-imid~zo-t2~l-b) thiazole-6~car~oxylato~
~xample 15 0041 g of glycine methyl ester chl~hydrate ~re di~solved in ~ ml of water. The ~olution obt~insd i~ neutralio~d wlth sodium bicarbonatc to p~ 7 ~nd the~ extracted quickl~
~ith 2 time~ 10 ml o~ ¢hloroform, A boiling 601ution o~
1 B Of 3-methyl-imidazo-(2,1-b)thi~zole-6-carboxylic acid obtained ao d~scribed i~ Ex3zple 10 in 25 ml of ~thanol i~
sdded to the Above sxtractO A~ter drying on sodium sul~ate the solvent ie eYapor~ted to yi~ld lo 2 g of oily~ wate~-~olubl~ methgl-flmmon~u~ethanoate-3-m~thyl-lmida~o-(2,1-b) thia~ole-6-carbo~ylate.
Exam~le 16 To a ~olution of 6.3 g o~ phosphorus pentachloride in 120 ml o~ dry methylene chloride, 5 g of 3-methgl-imidazo-(2,1~b)thiazole-6-carbo$yli~ sGid(prepared a~ described in ~ample 10) i~ sdd0d and the ~uspe~sio~ obtainsd i~
re~luIed ~ox 3 houroO After vacuum evaporatio~ of the eolvent th~ re~idue obtain~d bei~g 3-methyl-imidazo (2~1-b) thiazole-6-c~rbo~ylchlorido ~h~e~ohydrato ~ di~olved i~
100 ml o~ ab~Oethanol and the ~olution i~ re~lu~ed ~or

4 houre. The solvent i~ removed and the re~idue obtained i~ di~olved i~ wat~r- The ~olutio~ obtained iB neutra-li~ed to p~ 7.5 to yicld 5 ~ o~ 3-methyl-6-cArboethoxy_ :
~midazo-(2~1-b)thiazola; mOp 117-119.
:.

.
.. , , . .: , . . . .

- - ~.9 -105;~Z39 Esam~le 17 In a manner analogou~ to that de~cribed in ~xample 16 4.8 g of 3-methyl-6-carbopropo~y-imidazo-(2~1-b)thiRzole ara prepsred; m.p. 79-81.
E~am~lo 18 In Q ma~ner analogou~ to thst deecribed in Exa~ple 16 .5. g of 3-m~thgl-6-carboieopropo~y-imidazo-(2,1 b) thiazole ~re prepsred; m.p. 96-98 (the reaction tim~
betwee~ the acyl chloride and the alcohol is about 24 hour~) r Esam~le 19 .. :.... ..
In a man~er a~alogou~ to that de~cribed in E~smple ;
16 4,~ g o~ 3-metbyl-6-carbo~uto~y-imidazo-(2,1-b)thiazole ar- prepared; m.p. ~9-83.
E~am~le 20 In a manner ~nalogou~ to that de~cribed in Example 16 4.2 g o$ 3-methyl-6-carboisobuto~g-imidszo-t2~l-b) thiazolo are prepared; m.p. 80.5-81.5(hexane).
amDle 21 In a manner analogou~ to that de~cribed in Example 16 4~5 8~of 3-methyl-6-sec.~carbobutoxy-imidazo-(2,1-b) thiazole ~re prepared; m.p. 84-86(hexsne). (The reaction tima between the~3-me~thgl-imldazo-(2,1-b)thiazole-6-carboxyl chlorid~e: ~nd the sea.butenol i~ about 14 hour~).

In a~manner ~ alogous to that described in Example 16

5.5 B of~3-methyl-6-carbooctanoxy-imidazo-(2,1-b)thiazole ~r- prepared~ m.p- 72-75(hexane/petroleum ether)0 3samDle ~23 In~a~manner a~alogoue to that desoribed in Example 13 4.5,:g~'of~:3-methyl-6-carboGyclohexanox~r-imidazo-(2,l-b)thiazole `are;-prepared; m.p. 127-129(he~ene/chloroform).

. . - . . . ................................ ..
. ~; , . . . . :

iOS~Z3~

li XamD 1 ~ 2 4 100 ml of dry ethyl ami~e i~ dropped into the acyl chloride obtained a~ de~cribed in Example 16 and the temperature i~ k~pt at -20~ The ~olution obtalnad ia ~tirred for 1 hour at 0 and for 1 hour at 10~ The eolv~nt i8 th~n evaporated and the reeidue i~ nsutralised with a~ aqueou~ sodium carbonate 801utio~ a~d then sstracted with ehloro~orm. The eolvent i8 thon remo~ed and an oil i~ obtam ed. Said oily re~idue iB di~301ved i~ ethyl acetat~ and conc.nitric acid ~a sdded by way of dropping until the p~ ie 3~6 g of 3-mathyl-6-ethyl-carbox~mid~-imidazo-(2,1-b)thiazol~ nitrat~ sre obtai~ed;
m.p. 135~139tm~thyl ethyl-ketone),(dee.) EXamP1e 25 In a manner analogou~ to thst de~cribed in E~a~ple 24 ~ :

6 g of 3-methyl-6~diethyl~arbosamide-i~idazole-(2,1-b)thiazole nitrat~ are prepared; m.p~l30-132(dec~) ~The reactio~ ie performed at the boiling temperature of diethylami~
_xam~le 26 a. 48 g oi 3-methyl-6~carbomethoxy imidazo-(2,1-b~thia~ole~ :
prep~red a~ de~cribed in E~amplo 8, suspended in 400 ml o~ dry tetrahydrofuran (THF~ i8 dropp~d into a ~u~pen~ion of 12 g o~ hiA1~4 i~ 150 ml of dry THF. ~he r~action temp~raturo i9 kept at 25-30. After the r~action ha~
t~rminated~ the ~u~peneion ia kept ~or 1 hour at room temperature and the excess ~iA1~4 ie deetroyed by addin~ ~;
ethyl aeetate and WBterO ~-. - . . ~ - . ......... ~ - . .

. .

iO5;~Z39 The suspension is filtered and the cake obtained is washed with hot ethanol and the combined solutions are concentrated to yield 34 g of 3-methyl-6-hydroxy-methyl-imidazo-l2,1-b)thiazole; m.p. 156-157(methyl-ethyl-ketone).
b. 100 ml of a 70% solution of NaAlH2(CH3OCH2CH2O)~
in benzene are dropped at 25 into a suspension of 25 g of 3-methyl-6-carbomethoxy-imidazo-(2,1-b)thiazole, prepared as described in Example 8, in 250 ml of dry THF.
The suspension is stirred for 2 hours at room temperature and thereafter 25 ml of water are slowly added~ The suspension is then filtered and the filtrate concentrated to yield 21 g of 3-methyl-6-hydroxymethyl-imidazo-(2,1-b) thiazole; m.p. 155-156(methyl-ethyl-ketone).
Example 27 10 g of 3-methyl-6-hydroxymethyl-imidazo-(2,1-b) thiazole prepared as described in one of the methods in Example 26, is refluxed for 2 hours in 100 ml of SOC12.
The solution is then cooled, 50 ml of ether are added to yield 11 g of 3-methyl-6-chloromethyl-imidazo-(2,1-b) thiazole hydrochloride; m.p~ > 280.
Example 28 3.4. g of 3-methyl-6-chloromethyl-imidazo-~2,1-b) thiazole hydrochloride, prepared as described in Example 27, is introduced with stirring into a cooled solution of 3.5 g of sodium phenate in 100 ml of THF. After about 1 hour the sodium chloride which precipitates is filtered off, the solvent is evaporated and acidic water is added to the residue. The aqueous solution is extracted, at pH 3-6, with chloroform. The pH is then raised to 7-7.5 105;~Z3~

~nd the aqueou~ ~olution i~ a~sin e~tracted with chlo-rofo~m. '~hi~ extra~t i8 dried a~d the ~olvent ia then evaporat~d to yield 4 ~ of 3-~ethyl-6-phenoxymethyl-lmid~zo-(2,1-b)thia~ol~; m-p~ 190-192(methyl-ethyl-ketone)~
Ex~mpl~ 29 3.4 g of 3-methyl-6-¢hloromethyl-imidazo-(2,1-b)thiazole are slowly added Lnto 50 ml of cooled and atirred morpholine.
The stirxing i~ continued ~or 1 hour at room temperaturo a~d anothor hour at 40-50. The ~u~pensio~ obtainsd i8 filter~d ~nd the filtrate ie ~v~porsted. '~he re~ldue obt~ined- -i~ diasolved in wster and the aqueoue ~olution obtained i~ extracted with chloro~o~m. The chloro~orm solution i~
wa~hed at pH 5-6 with wat~r and after drying it i~ ~va-porated. Ethyl acetate i~ added to the residu~ to yield 4.5 g of 3-methyl-6-morpholinomethyl-imidszo-(2,1-b)th1azole; ~ ;
m.p. 203-204(methyl-ethyl-keton~)0 A ~olutio~ o~ 5 g of 3-methyl-6-hydroxgmethyl-imidazo-(2,1-b3thiazele in 100 ml of dry ahloro~orm i~ dropped ~: -at 35 into a ~olution o~ 15 ml o~ butyroyl chloride and 12 ml of pyrid~ne i~ 75 ml of dry ¢hloroform. The su~pension ~ - :
. . . -obtained i~ otirred for 1 hour at room temperature and then - : ~:
filt~redO The filtrate i~ con~entrat~d by avaporation. The re~idu~ obtained i8 ~issolY2d in ab~.~ths~ol and a stream -~ ~ :
o~ d~y hydroahlorio acid i~ bubbl0d into the ~olution to yiald 4.5 g of 3-methyl-6-butyro~ymethyl-imidazo-(2,1-b) thiazole hydroohlorid~, ~.p. 126-128. :
.. . .

.- . . . .

iOS3Z39 Example 31 A solution of 5 g of 3-methyl-6-hydroxymethyl-imida~o-(2,1-b)thiazole in 100 ml of dry chloroform is dropped at room temperature into a solution of 20 ml of p-chloro-benzoyl chloride and 12 ml of pyridine in 75 ml of dry chloroform. The solution is stirred for 30 minutes at room temperature and filtered. The filtrate is concen-trated under vacuum; the residue obtained is dissolved in isopropanol and a stream of dry hydrogen chloride is bubbled into the solution to yield 6 g of 3-methyl-6-p-chlorobenzoyloxymethyl-imidazo-(2,1-b)thiazole hydrochloride; m.p. 198-19g.
Example 32 15.8 g of 2-mercapto-4t5)-carbomethoxy-imidazole are suspended in a solution of 15.8 g of bromomethyl-ethyl-ketone (prepared by brominating methyl-ethyl-ketone in the presence of an equivalent of potassium chlorate in water; m.p. 75-80/60 mm Hg; 103-105/150 mm Hg) in 100 ml of abs. ethanol. The suspension obtained is stirred for 1 hour and then allowed to stand over night at room temperature. The solvent is then evaporated. The resldue is dissolved in water, then neutralised with an aqueous 5~ sodium carbonate solution until pH 6.5 is obtained. The solution is extracted with chloroform and the chloroform is then evaporated in order to yield 23 g of the~semicrystalline 4(5)-caxbomethoxy-2-(~-methylacetonyl-thio)-imidazole.~ Said compound is refluxed for 5 hours in 230 ml of phosphorus oxychloride. The solvent is then evaporated; ice-water îs added to the residue and the solution is neutralised with sodium carbonate to yield 16 g of 3-ethyl-6-carbomethoxy-imidazo-(2,1-b)thiazole;
m.p. 147-149 (ethyl acetate).

.

lOS;~Z39 Example 33 15.8 g of 2-mercapto-4(5)-carbomethoxy-imidazOle are suspended in a solution of 16.5 g of bromomethyl-propyl-ketone (prepared by brominating methyl-propyl-ketone in the presence of an equivalent of potassium chlorate in water; b.p. 88-94/50 mm Hg) in 100 ml of abs~ ethanol.
The suspension is then stirred for 2 hours at room temperature and the solution obtained is allowed to stand over night. The solvent is then evaporated. The residue obtained is dissolved in water, th~n neutralised with an aqueous 5~ sodium carbonate solution. The solution iS
then extracted with chloroform and the chloroform is e~a-porated to yield 24 g of oily 4(5)-carbomethoxy-2-(~ -ethyl-acetonylthio)-imidazole.
Said oil is refluxed for 3 hours in 250 ml of phosphorus oxychloride. The solvent is evaporated under vacuum; ice-water is added and the solution obtained is neutralised with sodium carbonate and extracted with chloroform. The solvent is evaporated to yield 14 g of 3-propyl-5-carbomethoxy-imidazo-(2,1-b)thiazole; m.p. 149-150(abs. ethanol).
Example 34 15.8 g of 2-mercapto-4(5)-carbomethoxy-imidazole are suspended in a solution of 18 g of a-bromomethyl-t.-butyl-ketone (prepared by brominating pinacoline in the presence of catalytic amounts of anhydrous aluminium chloride; b.p. 88.
5-90/17 mm Hg) in 100 ml of abs. ethanol. The suspension obtained is stirred for 1/2 hour at room temperature and then allowed to stand over night. The bromohydrate of 4(5)-carbomethoxy-2-( ~, y, ~ ,-trimethyl-acetonylthio)-imidazole precipitates and is filtered off. After neutralisation of the salt 19 g of the free base is obtained; m.p. 110-111(ether).

- ~' -. ' ' ": ,' lOS3Z39 The above base is refluxed for 12 hours in 190 ml of phosphorus oxychloride. (The cyclisation reaction is not complete and some starting product can be found at the end of the reaction`.) The solvent is evaporated under vacuum; the residue is dissolved in ice-water and the solution obtained is neutralised with sodium carbonate and then extracted with chloroform. The residue obtained after the evaporation of the solvent is chromatographed on neutral aluminium oxide and eluted with a chloroform/
petroleum-ether 40-60 mixture (20/80) to yield 5.4 g of 3-t.butyl-6-carbomethoxy-imidazo-(2,1-b)-thiazole;
m.p. 134-135.
Example 35 A solution of 15.8 g of 2-mercapto-4(5)-carbomethoxy-imidazole and 22 g of ~-bromo acetophenone [prepared as described in Zhuk.Obshch.Khim 33, 1135 (1963)] in 100 ml of abs.ethanol is stirred ~or 2 1/2 hours at room temperature.
30 g of 4(5)-carbomethoxy-2-phenacylthio-imidazole hydro-bromide are filtered off.
The free base, crystallised from acetone, is refluxed for 5 hours in 250 ml of phosphorus oxychloride. The solvent is evaporated under vacuum. The residue obtained is dissolved in ice-water, the solution is neutralised with sodium bicar-bonate until pH 6 is obtained a~d then extracted with chloroform.
The extract is dried and the solvent is evaporated to yield 21 g of 3-phenyl-6-carbomethoxy-imidazo-(2,1-b)thiazole;
m.p. 172-173(acetone).

lOS;~Z39 Example 36 A solution of 15.8 g of 2-mercapto-4(5)-carbomethoxy-imidazole and 25 g of W -bromo-p-chloroacetophenone (prepared by brominating 17 g of p-chloroacetophenone in dioxane/ether 1:2)~in 150 ml of abs. ethanol i5 stirred for 2 hours at room temperature. 200 ml of ether are then added to yield 34 g of the hydrobromide of 4(5)-carbomethoxy-~-tp-chloro-phenacylthio)-imidazole.
30 g of the free base obtained from said hydrobromide is refluxed for 10 hours in 250 ml of phosphorus oxychloride.
The solvent is then evaporated under vacuum; ice and chloroform are added to the residue and sodium carbonate is slowly added to the solution until pH 7. The chloroform layer is separated, dried and evaporated to yield 17 g of 3-p-chlorophenyl-6-carbomethoxy-imidazo-(2,1-b)thiazole;
m.p. 229-230o(dec )(methanol)~
Example 37 A solution of 15.8 g of 2-mercapto-4(5)-carbomethoxy-imidazole and 29.7 g of W -bromo-p-phenyl-acetophenone (prepared by brominating 21 g of p-phenylacetophenone in dioxane/ether 1:2) in 400 ml of abs. ethanol and 250 ml of dry methylene chloride is stirred for 2 hours at room temperature.
37 g of the hydrobromide of 4(5)-carbomethoxy-2-(p-phenyl-phenacylthio)-imidazole is obtained.
29 g of the free base obtained from said hydrobromide is refluxed for 7 hours in 300 ml of phosphorus oxychloride.
The solution is then worked up in the manner described in Example 36 to yield 22 g of 3-p-phenyl-phenyl-6-carbomethoxy-imidazo-(2,1-b)thiazole; m.p. 186-188(acetonitrile).

10~3Z39 ExamPl~ ~8 A ~olution of 15.8 g of 2-mercspto-4(5)-carbometho~y-imidazole and 25 g of ~I-bromo- ~-aGeton~phtone~p~pared a~cordi~g to J~O~Co llt 21 (1946)7 iI~ 150 ml Of' abYo ethanol i~ ~tirred for 2 hour~ at room temp~rature~
25 g of the hydrobromide of 4(5)-carbomethoxy-2-naphtha-~ylthio-imidazole i~ obtained. Said ~alt i8 neutrali~ed to yield 21 g of the freo base; mOp. 162-163.5(ab~ethanol)~
~ l'he ba~e i8 r~fluxed at l~ast 36 hours in 200 ml of phosphoru~ oxychloride and the solution is then worked up i~ a manner 8imilar to that descriDed in E~ample 36 to yield 1~ g of 3-t~ -naphthy1)-6-~arbomethoxy-imidazo-(2,1-b)thiszole; m.p. 187-188.
ExamPle 39 15 o8 g of 2-mercapto-4(5)-carbomethoxy imidazole are su~pended in a solution of 19 g of~1-bromomethyl-~-furyl-ketone (prepared by bromi~ating methyl~-furyl-~eto~e in dioxane~ether) in 150 ml of ab~.~thanol and the ~uspensio~ i~
the~ ctirred for 2 hours at room temperatur~ to yield 26 ~ of the hydrobromide of 4(5~-carbomethoxy-2~ furacylthio)-imidazoleO A~ter neutraliaation 20 g of the free ba~e aFe obtained; m.p. 139-141(ethyl scetate). ~ :
The base i8 refluxed for 12 hours in 200 ml o~ phosphorus o~ychloride~ The solvent i8 then evaporated under racuum, the residue i8 di~olved in watsr and 3-(2'-furyl)-6-carbometho~y imidazo(2~1-b)thiazole hydrochloride i~ filtered off. A~ter neutralisstion the ~ree ba~e i~ obtained; mOpO 169-170 (methyl-ethyl-ketone)~ :

- . - . . . . ........ . . . ..
-, . . ..

Example 40 15.8 g of 2-mercapto-4(5)-carbomethoxy-imidazole are suspendea in a solution of 20.5 g of W -bn~methyl --thienyl-ketone (prepared by brominating methyl-a-thienyl-ketone in dioxane/ether) in 150 ml of abs.ethanol.
The suspension is then stirred for 2 hours and thereafter allowed to stand over night at room temperature to yield 26 g of the hydrobromide of 4(5)-carbomethoxy-2-(a-thienacylthio) imidazole.
Said salt is dissolved in water, the solution is neutralised with sodium carbonate and extracted with chloroform. The extract is evaporated to yield 22 g of the free base;
m.p. 125-126(ethyl acetate).
The base is refluxed for 10 hours in 200 ml of phosphorus oxychloride. The solvent is then evaporated under vacuum.
The residue is dissolved in ice-water, the solution obtained is neutralised with sodium carbonate and extracted with chloroform. The solvent is evaporated to yield 17.5 g of 3-(2'-thienyl)-6-carbomethoxy-imidazo-(2,1-b)thiazole;
m.p. 161.5-163.0(abs.ethanol).
Example 41 15.8 g of 2-mercapto-4(5)-carbomethoxy-imidazole and 21.45 g of ethyl bromopyruvate are dissolved in 200 ml of abs.ethanol and the solution is stirred for 2 hours .
at room temperature~ The solvent is evaporated, water and chloroform, are added to the residue and the solution obtained is neutralised with sodium carbonate. After extraction with chloroform, drying, decolourisation and evaporation of the solvent 36 g of ethyl--oxo-[4(5)-carbomethoxy-2-imidazolyl]-thiopropionate are obtained.

' lOS3239 Said compound is refluxed for 2 hours in 360 ml of phosphorus oxychloride. The solvent is evaporated and water and chloroform are added to the residue. The solution is neutralised with sodium carbonate and then extracted with chloroform. The chloroform is then evaporated to yield 18.5 g of 3-carboethoxy-6-carbomethoxy-imidazo-(2,1-b)thiazole; m.p. 187-189(ethyl acetate).
Example 42 A solution of 15.8 g of 2-mercapto-4(5)-carbomethoxy-imidazole and 20.9 g of ethyl- ~-bromo acetoacetate in 250 ml of acetonitrile is stirred for 24 hours at room temperature. After decolourisation the solvent is evaporated and the residue is dissolved in a mixture of chloroform and water; sodium carbonate is then added until pH 7.5 is reached. The water phase is extracted several times with chloroform and the chloroform phase sometimes with water.
The chloroform extracts are combined, dried and the solvent is then evaporated to yield 32.5 g of oily ethyl-2-[4(5)- -carbo ethoxy-2-imidazolyl1-thioacetoàcetate.
;The oil~ia refluxed for 15~minutes in 180 ml of phos-phorus~oxyohloride. The solvent is evaporated, under vacuum, the res~idue is dissolved in water and the solution obtained~i~s-neùtralised~with sodium bicarbonate and extracted with chloroform. The chloroform extract is dried, the solvent~is evaporated and the residue obtained is dissolved in;a benzene-ether mixture. The solution is concentrated to y;ield~14~ g~of;~ethyl-6-carbomethoxy-imidazo-(2,1-b)thiazole-3-acetate; m.p. 152-154.

, ~053239 Example 43 A solution of 15.8 g of 2-mercapto-4(5)-carbomethoxy-imidazole and 16.6 g of ~-bromovaleraldehyde (prepared by direct bromination of n-valeraldehyde; b.p. 36-38/4 mmHHg) in 100 ml of abs. ethanol is stirred for 24 hours at room temperature. 4.5 g of the unreacted imidazole are filtered off, the solvent is evaporated and the residue dissolved in a water-chloroform mixture. The solution is neutralised with sodium carbonate and extracted with chloroform. The chloroform is evaporated to yield 11 g of 4(5)-carbomethoxy-2-(a-formylbutylthio)-imidazole; m.p. 160-162.
Said compound is refluxed for 4 hours in 110 ml of phosphorus oxychloride~ The solvent is evaporated. The residue obtained is dissolved in ice-water and the solution is neutralised with sodium carbonate to yield 10.5 g of 2-propyl-6-carbomethoxy-imidazo-(2,1-b)thiazole; m.p.
155-156(methyl-ethyl-ketone).
Example 44 A solution of 15.8 g of mercapto-4(5)-carbomethoxy-imidazole and 15.1 g of a-bromoethyl-methyl-ketone(prepared in an analogous manner to that described in Example 32;
b.p. 87-88/150 mm Hg) in 120 ml of abs.ethanol is stirred for 2 hours at room temperature and then allowed to stand over night. The solution is then evaporated, the residue obtained is dissolved in water and the solution is neu-tralised with sodium carbonate and extracted with chloroform.
The chloroform is evaporated to yield 23 g of semicrys-talline 4-(5)-carbomethoxy-2~ methyl-acetonylthio)-imidazole.

Said compound is refluxed for 3 hours in 230 ml of phosphorus oxychloride. The solvent is evaporated, the residue is - , ' . . . ' ~ ' .

~(~S;~Z39 dissolved in ice-water and the solution is neutralised with sodium carbonate to yield 17 g of 2,3-dimethyl-6-carbomethoxy-imidazo(2,1-b)thiazole; m.p. 180-181 (abs.ethanol).
Example 45 A suspension of 15.8 g of 2-mercapto-4(5)-carbomethoxy-imidazole in a solution of 16.5 g of ~-bromopro-pyl-methyl-ketone(prepared in analogous manner to that described in Example 33; b.p. 76-82~/50 mm Hg) in 100 ml of abs. ethanol is stirred for 2 hours at room temperature and allowed to stand over night. The solution obtained is evaporated and the residue is dissolved in water. The solution is neutralised with sodium carbonate and extracted with chloroform. The extract is evaporated to yield 22 g of 4(5)-carbomethoxy-2-(a-ethyl-acetonylthio)-imidazole; m.p. 105-106.
Said com~ound is refluxed for 2 1/2 hours in 200 ml of phosphorus oxychloride. The solution is evaporated, the residue is dissolved in ice-water, the solution obtained is neutralised with sodium carbonate and extracted with chloroform. The solvent is evaporated to yield an oil which upon washing with ether yields 14 g of 2-ethyl-3-methyl-6-carbomethoxy-imidazo-~2,1-b) thiazole; m.p. 94-95~.
In a similar manner the following compounds were prepared:
2-propyl-3-methyl-6 carboethoxy-imidazo-(2,1-b)thiazole 2-butyl-3-methyl-6-carboethoxy-imidazo-(2,1-b~thiazole 2-isoamyl-3-methyl-6-carboethoxy-imidazo-(2,1-b)thiazole ~ 32 -105;~Z39 ~xamPle 46 A ~olution of 15.8 g of` 2-mercapto-4(5)-carbomethoxy-i~nidazole and 23.4 g of ~-bromobenæyl-methyl-ketone i~ 150 ml of abs. ethanol is ~tirred ~`or 1 hour at room temperature. The ~olvent i~ di~tilled off and the residue is dis~ol~ed in water. 'L`he ~olution i~
neutrali~ed with eodium :' ~

;~ .

' ' ' ' . ' : .
.. .

.. ....

:, . ... .
. .

lO5;~;Z39 carbonate and extracted with chloroform. The extract is dried and the chloroform is evaporated to yield 38.5 g of an oil being 4(5)-carbomethoxy-2-(a-phenyl-acetonylthio) imidazole.
The oil is refluxed for l hour in 200 ml of phosphorus oxychloride and the solvent is then evaporated under vacuum. The residue is dissolved in ice-water and sodium bicarbonate is adaed to the solution obtained until pH 7.5. The solution is extracted with chloroform. The extract is dried and evaporated to yield 17 g of 2-phenyl-3-methyl-6-carbomethoxy-imidazo-~2,1-b)thiazole; m.p. 155-157 (ethyl acetate).
Example 47 A solution of 15.8 g of 2-mercapto-4(5)-carbomethoxy-imidazole and 17.7 g of a-bromo cyclohexanone in 150 ml of dry butanol are heated at 80 for 1 hour. The solvent is then distilled off under vacuum and the residue obtained is dissolved in water. The solution obtained is neutralised with sodium carbonate and extracted with chloroform. The extract is dried, the solvent is evaporated and the residue is chromatographed on an alumina column to yield 14.5 g of 2-carbomethoxy-imidazo-(2,1-b)-5,6,7,8-tetrahydro-benzothiazole;
m.p. 97-99(petroleum-ether/ether mixture).
Example 48 0.5 g of NaBH4 are slowly introduced in a stirred solution of 5.5 g of 4(5)-carbomethoxy-2-acetonylthio-imidazole (prepared as described in Example 8b) in 60 ml of methanol.
The temperature is kept at 5-10~. The solution is stirred for 1 hour at said temperature and then the solvent is evaporated.

10~3Z39 ~ 34 _ Water i~ added to the re~idue and the 801ution i~
neutrali~ed with 80dium carbonate to yield 5.2 g of 4(5)-c~rbomethoxy-2-( ~-hydroxy-propylthio)-imidazole;
m~p. 153-154. ~ ~
Said compound iB re~luxed for 2 hour~ i~ 55 ml oi -~ -phosphorus oxychloride and the residue obtained a~ter the evaporation of the ~olvent i~ di~solved in ice-water.
'l'he ~olution obtained i~ neutralised with ~odium carbonate and extracted with chloroform. '~he extract i~ evaporated and 3.2 g of 3-methyl-6-c~rbomethoxy-imidazo-(2tl-b)~
2,3-dihydrothiazole are obtained; m.p. 94-95(ether).
~xamPle 49 4.~ g of ~,3-dimethyl-6-carbomethoxy-imida~o-(2,1-b) th$azole(prepP~ed a~ de~cribed Ln Example 44) Pr~ -refluxed for 2 hours in 25 ml of 10~ NaOH. The ~olution obtalned i8 cooled to 40 and acetic aoid i8 dropped into the solution u~til the pH is 5. I~he solution i~ then cooled to yield after filtrstion 4~1g of 2,3-dimethyl-imidszo-(2,1-b)thiazole-6-c~rboxylic scid; m.p. 260-261.
~xamPle ~0 1,5 g of 2-ethyl-3-methyl-6-carbomethoxy-imidazo-(2,1-b)thiazole(obtained ae described in E~ample 45) sre refluxed~for 2~hours;in 5 ml of 10~ NaOH. The ~olution obtained ie treated in the e&me manner as de~cribed in xample 49 to yie}d 1,2 g of 2~ethyl-3-methyl-i~ldszo-(2,1-b~thiazole-6-carboxylic acid m.p. 243-245C.
xamDle 51 2.1 ~ of` 2-ethyl-3-methyl-imidszo-(2,1-b)thlazole-6-carboxyl~o aoid obtsined a~ de~oribed in Example 50~ are refluxed~in 50 ml of ethanol and a solution o~ 1.2 g of 2-amino-2-(hydroxymethyl)-1,3-propanediol in 10 ml of ethQnol~ia added. 'l'he solvent i~ then evaporsted to yield 3 g of 2'-thydroxymethyl)-1',3'-propanediol-2~-ammonium-2-.~.. , . , .. , ., , .... ~ ., , .. . . . l . -~0 53Z 39 ethyl-3-methyl-imidazo-t2,1-b)thia~ole-6~carboxy1ate;
m.p. 164-165(ieopropenol).
ample 52 1 g of 2-ethy1~3-dimethyl-imidazo-(2~1-b)thiazole-6-¢arboxylic scid obtai~ed as de~cribed in Example 50 are re~luxed in 20 ml of e~ha~ol and s ~olution of 0.7~ g o~ trietha~ol~in~ in 5 ml of ethanol ie sdded to the ~olution, 'lhe solve~t i~ then evaporated ~nd an oily aalt being triethanol~mmonium-2-ethyl-3-methyl-imidazo-(2~1-b)thiazole-6-c~rboxylate i~ obtained. --ExamDle 53 2,5 g o~ 2,3-dimethyl-imidazo-(2,1-b)th~azole-6-carbo~yl~c acid (prepared ae desoribed in ~xample 49) are added to a solution o~ 3~3 g of phosphoruo pentachloride in 70 ml of dry methylene chloride and the sUspen~ion obt~ined i8 refluxed for 3 hours. A~ter vacuum evaporat~on of the eol~ent~
the re~idue is dieaolved in 100 ml of abe. ethanol and the eolution ie the~ refluxed for 24 hours. The solvent ie then evaporated snd the reeidue ie~dis~ol~ed in water and the ~olution io neutrsli~ed with NB2CO3. After extraction with ohloro~orm snd e~aporation to drynes8~ 2~1 g of 2~3-dimethyl~6-carboethoxy-lmld~zO-(2~1-b)thiazolo are obtainedS
m.p. 108-110C(a¢etone).

In a msnner analo~uo to thst de~cribed in ~xamplo 53 there are prepared ~rom 5 g of 2-ethyl-3-methyl-lmidazo-(2~1-b)-thla&ole-6 carboxylia aoid ~prepared às dee¢r~bed in ~xample 51) 4,8 g oi 2-ethyl-3-m~thyl-6-earboethoxy-imidazo-(2~1-b)th~-a~Ole`, m.p. 64-65(ether~petrol ether), . :- : - : .
... ... , :, . , . ~. , 105;~Z39 100.000 Tablets are prepared utili~ing the following substance~:
A. 3-~ethyl-imidazo-(2,1-b~thiazole-6-carboxyli~ :
acld 25 kg Am~lum B~P.
Lactose B.P. 15 "
B. ~ranulate with 10~ mucilage Amylum C. Amylum ~P. 2 "
D. Amylum B.P. 2 "
'l`al~ ~.P. 2 "
~iagnesium ~tsarate ~he tablet~ are prepared a~ follows: ~ -~ ubstances A and ~ are gra~ulated togetherO Therea~ter compound C ia added which yield~ a WEt granulate mix. '~'his mix i8 dried a~d then crushed. Compound~ D are the~ admixed with the pre~iou~ mix snd tablet~ are prepared from the final mix~
~ - ~
100.000 Long-acting tablet~ are prepared utili~ing the ~ollowing sub~tance~
A. 2-~thv1-3-methy1-6 c~rboethoxy-imidazo-(2,1-b) thiazoIe 25 kg . Oleum '~h~obrom 1 "
Car~auba Wax Psle 1~3~
Cexa Alba ~.P. . 1.3"
.

~ ' ~' ', ;. ' .
, '' - - : : - ; . - . . .
... . . - . .. . . . ..

.

1053239 q Stearic ~oid $riple Pres~ed 006 kg Non emul~i~ying Glyceryl ~onoatearate 1.6 "
Trichloroethylene 3 "
C. ~agn~sium Stearate 006 "
Csrborol 3 The tablet~ are prepared as follows:
Sub~tances A and B are granulated to~ether~ The mi~ture obtained i~ dried and then crushed. The ¢rushed mixture i~ admixed with eub~ta~0s C. Tsblet~ are prop~r~d from the miYture obtai~ed.

.~ .
.~. .

.... .. . .... - .................... ..

~xa~pl~ 57 So-ne o~ the new compounds according to the pre~ent invention were tested on diabetic alloxan treated rats (blood gluco~e conce~tration 250-450 mg/100 ~ diabetic rat~. in the test a 200 mg/kg do~e wa~ orally a~ministered and a curve re~pon~e do~e WaB then performed.
Ihe blood gluc0~3 concentration was determined at 0-5-24 hours a~ter the oral a~ninistrationO In some cases a curYe time response was determined at 0-3-5-8-24 hours.
'l'he influence of the product~ on hypRrglicaemi~
gluco~e-loaded rat~ and on normal rat~ by oral or intraperitor~al administration was aloo determined for s~ne compound~. The ~luco~e concentration in the urine wa~
also ohecked ~ld in many case~ the general pharmacological screening wa~ carried out.
~ ome of tne r~ults are given in the ~ollowing ~ablea I - V, where ~ mea~ i8 the mean diminution~
of the blood glucose concentration (mg/100 ml ) in ~n~
experiment~ at the cited hour and :
~ ~h mean ~mean.100 mean ~tarting blood glucose concentration All compound~ sre tho8e of formula I and ~ubqtituent~ A, B~
C and D refer to tho~e givcn in 9aid formulaO

:' ' .

. .
' ':. ' , : .

~0~3Z39 Diabetic - alloxane treated rat_ A B C D n dose P.O. hours after a~niStration . mg/kg 5 _ 24 A /\% _ /\% _ COOCH3 H 3 H 62 200 104 24% 23 2 5 H . CH3 H 10 50 40 10 100 81 1~ .
200 139 39% 37 .
2 5 H CH3 H 15 200 165 48% 13 COOCH(CH3)2 H 3 H 20 200 118 36 COOCH2CH(CH3)2 HCH3 H 10 200 135 37% 60 16%
COoH.HCl H CH3 H 15 200 160 49% 15 COOH H CH3 H 40 200 118 35% 44 COoNH3C(CH2OH)3 H3 H 15 60 47 13 :.
. 15 120 90 25 180 115 32% 33 CH20oOC3 7 H 3 H 10 200 73 . O
CH2CCO~C11P) H 3 H 15 200 100 O
COOCH3 H C(C~3)3 H 10 200 80 31 COOCH3 H C6H5 H 10 200 72 10 . .
oCDCH3 H HC3H ¦10 200 73 7 H CH3CH3 10 200 142 41% 67 20%
3C( ~ oH)3 H CH3 C2H5 15 30 30 O
: 15 60 70 25 180 150 46% 50 15%
: 15 360 150 44% 104 2~%
. ' .' ' ~

~40- ~oS3Z39 TABLE I (continuation) A B C D n dose P.O. hours after administration L LL L~A` 2 ~ _ :
COOC2H5 H 3 C2H~ 10 100 73 . _ 200 14445% 80 25%
400 176s2% 97 2S%
2 5 H 3 C2H5 15 200 14646% 29~10%
COOC2H5 H 3 2 2 (C 3)2 15447% 87 27%

(+~ H 3 C ~5 10 200 8321% 64 16%
oooNH(~H2cH2cH)3 5 Cs3 C2N5 10 200 17050~ O _ CbntnDl phenfbrium 135 200 9928% 0 -T~BIE II
Diabetic-gluoose loaded rats :
COOC2 5 H 3 H 10 100 53% O -COOC2H5.HCl H CH3 C2H5 10 100 34%

CnCNH3C(CH2oH)3 H 3 C255 ~ 100 - ~ ~ ~

~3LE III ~ :
Nb.~mal rats CX C2nS H 3 ¦ 5 ¦ 10 ¦ 200 23 oooH H CH3 H 10 200 14~5 ¦ 5 ¦
C~20CC~Cl(P) H CH3 H - 10 200 17 ¦ 14 ¦
COCH.HCl H CH3 H 10 lOOIP _ 2~ ¦ O
COO 2 5 H CH3 C2H5 10 ~0 I.P.... _ 24% ¦ O
(+~ lOOI.P. _ >70% ¦ 0 ¦ 5 CNH~(C1;:)3 ~NCN3 ~C2N5~10 ¦IOOI-P-! ~389c ~0 ~15 `` 105;~Z3~

~13LE IV
Influence of starting blool glucose ooncentration on - ~ mean and ~ ~ mean (5 hours after per os administratian) A C D dose starting blood gluc3se concen-P.O. tration ~ 290 290-380 > 380 ~ _ _ A% ~ ~

oOCH H CH3 H 200 85 37 156 45 196 48 CH2OCO~Cl(P) H 3 H 200 47 17 105 34 125 35 ~ ~ :
COOC285 H 3 C23! 200 120 41 145 43 165 41 controI phenform m e 200 135 44 95 26 50 8 ~E V
Influence of time on ~ nean in diabetic alloxane-treated rats .

COOC2H5 H CH3 H200 5 hours ~ ~ 139 8 hours ~ = 45 24 hours ~ = 37 COGH H CH3 H200 5 hours ~ = lla . ~
8 hours L_~ = 69 24 hour~ ~ = 44 oOOC2H5 H 3 C2N5 200 3 hours ~ = 82 5 hours ~ = 144 8 hours ~ = 107 24 hours ~ = 80

Claims (14)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A process for the preparation of an imidazo-(2,1-b) thiazole of the general formula I

(I) wherein A stands for one of the following radicals:
(CH2)nCOOR, (CH2)n CON, (CH2)n CN, (CH2)n CF3, (CH2)nCH2X, (CH2)nCH2OCOR1 in which:

n is 0, 1 or 2 R stands for a straight or branched alkyl, phenyalkyl, cyclopentyl or cyclohexyl radical or for a hydrogen atom;
the N group stands for an unsubstituted or alkyl sub-stituted amino, 5 or 6 member saturated cyclic amino optionally comprising an O atom or it stands for a hydrazino group;
X stands for a halogen atom or for a hydroxy, mercapto, alkoxy, phenoxy or phenylalkoxy radical, or for a N group as defined above;
R1 stands for straight or branched alkyl, phenyl or a phenyl radical substituted by halogen, lower alkyl or a lower alkoxy radical;
substituents B,C and D stand for substituent A as defined above, for a hydrogen atom or for a naphthyl; phenyl;
phenyl substituted by a halogen atom or by lower alkyl, nitro or lower alkoxy radical; straight or branched alkyl, furyl or thienyl radical;
C and D together with the bond connecting them may stand for a moiety;

the dotted line standing either for two hydrogen atoms or for a C-C bond;
or one of the physiologically acceptable acid addition -or quaternary ammonium - salts; excluding 3,5-dimethyl-6-carbethoxy-imidazo(2,1-b)thiazole, in which (a) an .alpha.-halocarboxyl derivative of the general formula II

(II) wherein C and D are as defined above, Y represents a halogen, and the carbonyl group may be protected by a readily cleaved group, is condensed with a 2-mercapto-imidazole derivative of the general formula III

(III) wherein A and B are as defined above, to yield a thio-carbonyl derivative of the general formula IV

(IV) wherein A, B, C and D are as defined above, and when the carbonyl group of the halocarbonyl derivative of the general formula II was protected, the compound obtained is subjected to an acidic cleavage reaction; the product of the general formula IV is converted into the compound of the general formula I by cyclisation and dehydration, or (b) an .alpha.-halocarbonyl derivative of the general formula V

(V) wherein A and B are as defined above and Y represents a halogen atom, is condensed with a 2-amino-thiazole derivative of the general formula VI

(VI) wherein C and D are as defined above, or (c) when at least one of the substituents A, B, C and D
represents (CH2)2COOR wherein R represents an inorganic cation or an ion wherein E, E' and E" may represent hydrogen or the same of different hydroxyalkyl, alkyl, alkylamino, alkylcarbal-koxy or alkylcarboxy radicals, the corresponding imidazo-(2,1-b) thiazole carboxylic acid is dissolved in an inert solvent and a solution of an appropriate base is added to the solution, or (d) when the dotted line in the formula I represents two hydrogen atoms, a thiocarbonyl derivative of the formula IV as defined above is reacted with sodium borohydride to yield a .beta.-thioalcohol of the formula VII

(VII) wherein A, B, C and D are as defined above and the compound of the formula VII is cyclised and dehydrated before or after esterification, and, to prepare an acid addition salt, the compound of the formula I is reacted with a physiologically acceptable acid, and, to prepare a quaternary ammonium salt the compound of the formula I is reacted with a suitable ester of an acid.

2. An imidazo-(2,1-b)thiazole of the general formula I as defined in claim 1, and the physiologically acceptable acid addition or quaternary ammonium salts thereof, exclusive of 2-carbomethyl-3,5-dimethyl-6-carboethoxy-imidazo(2,1-b) thiazole ana 3,5-dimethyl-6-carboethoxy-imidazo(2,1-b) thia-zole, whenever obtained according to a process as claimed in claim 1 or by an obvious chemical equivalent thereof.

3. A process as claimed in claim 1 for the preparation of a compound of the formula I as defined in claim 1 and the physiologically acceptable acid addition or quaternary ammonium salts thereof, exclusive of 3,5-dimethyl-6-carboethoxy-imidazo(2,1-b) thiazole, in which an .alpha.-halocarboxyl derivative of the general formula II

(II) wherein C and D are as defined above, Y represents a halogen and the carbonyl group may be protected by a readily cleaved group, is condensed with a 2-mercapto-imidazole derivative of the general formula III

(III) wherein A and B are as defined above, to yield a thiocarbonyl derivative of the general formula IV

(IV) wherein A, B, C and D are as defined above and, when the car-bonyl group of the halocarbonyl derivative of the general formula II was protected, the compound obtained is subjected to an acidic cleavage reaction, the product of the general formula IV is converted into the compound of the general formula I by cyclisation and dehydration, and, to prepare an acid addition salt, the compound of the formula I is reacted with a physiologically acceptable acid, and, to prepare a quaternary ammonium salt the compound of the formula I is reacted with a suitable ester of an acid.

4. A process as claimed in claim 3 in which the reaction is carried out in a solvent at a temperature between room temperature and the boiling point of the solvent.

5. A compound of the general formula I and the physio-logically acceptable acid addition or quaternary ammonium salts thereof, excluding 3,5-dimethyl-6-carboethoxy-imidazo(2,1-b)thiazole, whenever obtained according to a process as claimed in claim 3 or claim 4 or by an obvious chemical equivalent thereof.

6. A process as claimed in claim 1 for the preparation of the compound of the formula I as defined in claim 1, and the physiologically acceptable acid addition or quaternary ammonium salts thereof, exclusive of 3,5-dimethyl-6-carboethoxy-imidazo(2,1-b)thiazole, in which an .alpha.-halocarbonyl derivative of the general formula V

(V) wherein A and B are as defined above and Y represents a halogen atom, is condensed with a 2-amino-thiazole derivative of the general formula VI

(VI) wherein C and D are as defined above, and, to prepare an acid addition salt, the compound of the formula I is reacted with a physiologically acceptable acid, and to prepare a quaternary ammonium salt the compound of the formula I is reacted with a suitable ester of an acid.

7. A process as claimed in claim 6 in which the reaction is carried out in a solvent at a temperature of from 0 to 150°C.

8. A compound of the formula I, and the physiologically acceptable acid addition salts or quaternary ammonium salts thereof, exclusive of 3,5-dimethyl-6-carboethoxy-imidazo (2,1-b)thiazole, whenever obtained according to a process as claimed in claim 6 or claim 7 or by an obvious chemical equivalent thereof.

9. A process as claimed in claim 1 for the preparation of the compound of the formula I as defined in claim 1, and the physiologically acceptable acid addition or quaternary ammonium salts thereof, exclusive of 3,5-dimethyl-6-carboethoxy-imidazo(2,1-b)thiazole, in which when at least one of the substituents A, B, C and D represents (CH2)2COOR wherein R represents an inorganic cation or an ion wherein E, E' and E" may represent hydrogen or the same or different hydroxyalkyl, alkyl, alkylamino, alkylcarbalkoxy or alkylcarboxy radicals, the corresponding imidazo-(2,1-b) thiazole carboxylic acid is dissolved in an inert solvent and an appropriate base is added to the solution, and, to prepare an acid addition salt, the compound of the formula I is reacted with a physiologically acceptable acid, and, to prepare a quaternary ammonium salt, the compound of the formula I is reacted with a suitable ester of an acid.

10. A compound of the formula I and the physiologically acceptable acid addition salts and quaternary ammonium salts thereof, exclusive of 3,5-dimethyl-6-carboethoxy-imidazo(2,1-b)thiazole, whenever obtained according to a process as claimed in claim 9 or by an obvious chemical equivalent thereof.

11. A process as claimed in claim 1 for the preparation of a compound of the formula I, and the physiologically acceptable acid addition or quaternary ammonium salts thereof, exclusive of 3,5-dimethyl-6-carboethoxy-imidazo(2,1-b) thiazole, in which when the dotted line in the formula I
represents two hydrogen atoms, a thiocarbonyl derivative of the formula IV

(IV) is reacted with sodium borohydride to yield a .beta.-thioalcohol of the formula VII

(VII) wherein A, B, C and D are as defined above and the compound of the formula VII is cyclized and dehydrated before or after esterification, and, to prepare an acid addition salt, the compound of the formula I is reacted with a physiologically acceptable acid, and, to prepare a quaternary ammonium salt the compound of the formula I is reacted with a suitable ester of an acid.

12. A compound of the formula I, and the physio-logically acceptable acid additions or quaternary ammonium salts thereof, exclusive of 3,5-dimethyl-6-carboethoxy-imidazo(2,1-b)thiazole, whenever obtained according to a process as claimed in claim 11 or by an obvious chemical equivalent thereof.

13. A process as claimed in claim 1 for the preparation of a compound of the formula I

(I) wherein A represents COOR" in which R" represents a hydrogen atom, a hydroxyalkylammonium or an inorganic cation, or a lower alkyl group; or CH2OCOR"' in which R"' represents an alkyl group, a phenyl group or a phenyl radical substituted by halogen, lower alkyl or a lower alkoxy radical;

B represents hydrogen, C represents methyl, tert.-butyl a phenyl group, or a phenyl radical substituted by halogen, lower alkyl or a lower alkoxy radical; and D represents hydrogen or an alkyl group, and the physiologically acceptable acid addition or quaternary ammonium salts thereof, according to any one of processes (a), (b), (c), and (d) wherein A, B, C
and D, in formulas II, III, IV, VI and VII are as defined above and, to prepare a physiologically acceptable acid addition salt, the compound of the formula I is reacted with a physiologically acceptable acid, and, to prepare a quater-nary ammonium salt, the compound of the formula I is reacted with a suitable ester of an acid.

14. A compound of the formula I, and the physiolog-ically acceptable acid addition or quaternary ammonium salts thereof, whenever prepared according to a process as claimed in claim 13 or by an obvious chemical equivalent thereof.