Compounds having a 5 membered, nitrogen containing ring with a thione group adjacent to a nitrogen atom substituted with an OR group have antimicrobial properties. Metal complexes or salts of these compounds also have antimicrobial properties. The compounds, or the metal complexes or salts thereof, can be used as a cutting fluid preservative, a wood preservative, in cooling water applications or as an antimicrobial agent in a paint. Some of the compounds are new. The metal complexes or salts are new.

The present invention relates to a class of compounds, some of which are 
new compounds, which are useful as industrial biocides. 
Industrial biocides are useful to prevent industrial spoilage, in 
particular that caused by bacteria and fungi. Materials which can be used 
as industrial biocides have antimicrobial properties and particularly have 
antifungal or antibacterial properties or preferably both antifungal and 
antibacterial properties. Such materials are useful in the preservation of 
paints, lattices, adhesives, leather, wood, metal working fluids and 
cooling water. 
British Patent Specification No. 1113634 discloses fungicidal compositions 
comprising an isothiazolothione in admixture with a solid diluent or a 
liquid diluent containing a surface active agent. The isothiazolothione is 
of the formula: 
##STR1## 
wherein R.sub.1 and R.sub.2 may, inter alia, together with their adjacent 
carbon atoms constitute a ring. Such ring systems include a cyclopentene 
or cyclohexane ring (compounds 8, 9 and 10) or a benzene ring (compounds 
11 to 43). However, it is indicated that such compounds may isomerise to a 
structure containing an oxime group. The structure of compounds of this 
type, such as compound 41 as disclosed on GB 1113634, has been studies and 
it is concluded, in Il. Farmaco-Ed.Sci., vol. 23, pp. 572 to 582, that in 
such compounds the oxime structure is more stable. 
British Patent Specification No. 1104893 discloses a biocidal composition 
in which the active ingredient is disclosed as being at least one 
3-imino-1,2-dithiole derivative, such as, for example 
3H-1,2-benzodithiol-3-one oxime and 
4,5,6,7-tetrahydro-3H-1,2-benzodithiol-3-one oxime. 
Cyclic compounds containing a thione group have been described in the 
literature but these other references do not indicate that the compounds 
possessed any antimicrobial activity. 
U.S. Pat. No. 3,448,116 discloses, as anticonvulsants, compounds such as 
1-hydroxyhydantoins and 1-hydroxythiohydantoins. J.C.S. Perkin 2, (1981), 
p. 92ff; Chem.Ber. (1964), 97, p. 216ff; Chem.Ber. (1971), 104, p. 1512ff; 
and Arch. Pharm. (1978), 311(1), p. 39ff describe cyclic compounds 
containing a thione group and having two nitrogen atoms in the ring 
adjacent to the thione group. J.C.S. Perkin I (1986) pages 39 to 59 
discloses, inter alia, N-hydroxythiazolinthione derivatives and the 
preparation thereof. However, there is no suggestion that the compounds 
disclosed have anti-microbial properties. 
We have now found that certain cyclic compounds containing a thione group 
and at least one adjacent amino-group have anti-microbial properties. Some 
compounds of this type are novel. 
According to the present invention, there is provided a biocide composition 
which contains at least one compound of the formula: 
##STR2## 
or a metal complex or salt thereof; wherein: 
A is a nitrogen or carbon atom, which may be substituted; 
B and D are, independently, oxygen or sulphur or a nitrogen or carbon atom 
which may be substituted; or 
A and/or B and/or B and/or D may be part of a ring system; 
R is hydrogen, a hydrocarbyl group, a substituted hydrocarbyl group, an 
acyl group, a substituted acyl group or a group --COOR.sup.1 ; and 
R.sup.1 is a hydrocarbyl group 
with the proviso that B and D are not both sulphur or both oxygen. 
The group A, and optionally one or both of groups B and D can be a group 
--C(R.sup.2).sub.2 --; a group --CR.sup.2 .dbd.; a group 
##STR3## 
a group --NR.sup.2 -- or a group --N.dbd.; where R.sup.2 is a hydrogen 
atom, a hydrocarbyl group, a substituted hydrocarbyl group or two groups 
R.sup.2, together with the carbon atom, or carbon atoms, to which they are 
attached form a ring. 
The groups A, B and D can form part of a further ring system but generally 
not more than two of the groups A, B and D form part of a further ring 
system. The further ring system is typically a hydrocarbon ring system 
containing five or six carbon atoms, for example a cyclopentene, 
cyclohexane, cyclohexene, cyclohexadiene or benzene ring. The further ring 
system, if present, typically contains one or both of the groups A and B. 
If only the group A forms part of a ring system, this may be a cyclohexane 
ring of the type 
##STR4## 
where the group A is the carbon atom with the two free valencies, which 
are linked to the group --NOR-- and B respectively. If both a and B form 
part of a ring system, the further ring is then fused to the azolethione 
ring system; for example as in 
3-hydroxy-4,5,6,7-tetrahydrobenzothiazol-2(3H)-thione. 
In many of the compounds used in the biocide compositions of the present 
invention, the groups A, B and/or D are not part of a ring system. Thus, 
if A, B and/or D is a carbon atom, or substituted carbon atoms, it may be, 
inter alia, a group --CH.dbd., --C(CH.sub.3).dbd., --C(C.sub.2 
H.sub.5).dbd., --C(C.sub.6 H.sub.5).dbd., --C(C.sub.6 H.sub.4 Cl).dbd., 
--C(CH.sub.3).sub.2 -- or 
##STR5## 
It will be appreciated that in the foregoing, the group R.sup.2 is a 
hydrogen atom, a methyl, ethyl, phenyl or chlorophenyl group. Typically, 
R.sup.1 is a hydrogen atom, a lower alkyl group, that is one containing up 
to five carbon atoms, an aryl group or a substituted alkyl or aryl group 
in which the, or each, substituent is a hydrocarbonoxy group, an acyl 
group, a ester (that is an acyloxy) group, a halogen atom, or a nitrile 
group. 
It is generally preferred that the groups A and B are both optionally 
substituted carbon atoms and the group D is a sulphur atom or optionally 
substituted nitrogen atom. The groups A and B are preferably linked 
through a double bond as in the group --CH.dbd.CH--. It is preferred that 
D is a sulphur atom. 
The group R may be a hydrogen atom, an acyl group such as benzoyl or acetyl 
or an alkoxycarbonyl group such as an ethoyxcarbonyl group. If the group R 
is a substituted group, it may contain a further ring system of general 
formula I, the two ring systems being linked through the group R, for 
example as in the glutaryl bis ester of the formula: 
##STR6## 
The biocide composition may contain a metal salt or complex of the compound 
of general formula I. The metal present in such a salt or complex may be 
any metal. Thus, the metal may be a transition metal, for example a metal 
of group VIII, IB or IIB of the Periodic Table. Such metals include iron, 
copper and zinc, particularly such metals in their maximum possible 
valency state. 
All reference herein to the Periodic Table are to the Periodic Table 
according to Mendeleeff, as set out on the inside rear cover of "General 
and Inorganic Chemistry" by J. R. Partington, Second Edition published by 
MacMillan and Co. Limited, London. 
For convenience hereafter, the compounds of the general formula I, and the 
metal salts and complexes thereof will be referred to simply as "compound 
I". 
A wide range of compounds I can be used in the biocide compositions of the 
present invention. The compounds I have anti-microbial activity against a 
wide range of micro-organisms including bacteria, fungi and algae. 
Compounds I which can be used in the composition of the present invention 
include: 
3-hydroxy-4-methylthiazol-2(3H)-thione, 
3-benzoyloxy-4-methylthiazol-2(3H)-thione, 
3-hydroxy-4-phenylthiazol-2(3H)-thione, 
3-hydroxy-4,5,6,7-tetrahydrobenzothiazol-2(3H)-thione, 
3-acetoxy-4-methylthiazol-2(3H)-thione, 
the glutaryl bis-ester of 3-hydroxy-4-methylthiazol-2(3H)-thione, 
5,5-dimethyl-1-hydroxy-4-imino-3-phenylimidazolidine-2-thione, 
1-hydroxy-4-imino-3-phenyl-2-thiono-1,3-diazaspiro[4.5]decane, 
1-hydroxy-5-methyl-4-phenylimidazoline-2-thione, 
3-ethoxycarbonyloxy-4-methylthiazol-2(3H)-thione, 
4,5-dimethyl-3-hydroxythiazol-2(3H)-thione, 
4,5-dimethyl-3-acetoxythiazol-2(3H)-thione, 
4-ethyl-3-hydroxy-5-methylthiazol-2(3H)-thione, 
4-ethyl-3-acetoxy-5-methylthiazol-2(3H)-thione, 
4-(4-chlorophenyl)-3-hydroxythiazol-2(3H)-thione, 
3-hydroxy-5-methyl-4-phenylthiazol-2(3H)-thione, 
3-acetoxy-4-phenylthiazol-2(3H)-thione, 
and the metal complexes and salts thereof. The metal complexes and salts 
thereof include ferric, cupric and zinc complexes and salts such as 
the zinc complex of 3-hydroxy-4-methylthiazol-2(3H)-thione, 
the ferric complex of 3-hydroxy-4-methylthiazol-2(3H)-thione, 
the cupric complex of 
1-hydroxy-4-imino-3-phenyl-2-thion-1,3-diazaspiro[4.5]decane, 
the cupric complex of 4,5-dimethyl-3-hydroxythiazol-2-(3H)-thione, 
the zinc complex of 4,5-dimethyl-3-hydroxythiazol-2(3H)-thione, and 
the zinc complex of 4-ethyl-3-hydroxy-5-methylthiazol-2(3H)-thione, 
The compositions of the present invention provide good wet state 
preservation making the compositions advantageous for use as a cutting 
fluid preservative and also in cooling water applications. Wood and 
leather preservation is another advantageous field of application of the 
compositions. The compositions of the present invention can also be 
incorporated into paint, as paint film fungicide and many of the 
compositions can be used without addition of a bactericide. 
The compounds I which are present in biocide composition of the present 
invention are soluble in many polar solvents, although the solubility is 
dependent on the nature of the groups A, B, D and R. However, many of the 
compounds I are soluble in water, alcohols, ethers, ketones and other 
polar solvents or mixtures thereof. 
The compositions of the present invention may consist only of the compound 
I. However, typically the composition comprises the compound I as a 
solution, suspension or emulsion in a suitable liquid medium such as 
water. The composition may comprise a suspension or emulsion of the 
compound I or a solution thereof, in a liquid medium in which the compound 
I is insoluble. 
The composition may be incorporated into the medium to be protected using 
any suitable mixing technique. The composition is incorporated into the 
medium to be protected in an amount to provide from 0.00002 to 5% by 
weight of the compound I relative to the total composition, more 
preferably from 0.00005 to 1% by weight of compound I. It will be 
appreciated that the quantity of compound I required will be dependent on 
various factors such as the medium to be protected, the micro-organisms 
against which protection is desired and the extent of protection required. 
If the composition is being used to preserve a solid substrate such as 
leather or wood, the composition may be applied directly to the substrate 
or may be incorporated into a coating composition such as a paint, varnish 
or lacquer which is then applied to the substrate. Alternatively, the 
solid material may be impregnated with the composition of the present 
invention. 
The compositions of the present invention can be used for the treatment of 
various media to inhibit the growth of micro-organisms. 
Thus, as a further aspect of the present invention there is provided a 
method for inhibiting the growth of micro-organisms on, or in, a medium 
which comprises treating the medium with a compound I as hereinbefore 
defined. 
The compound I can be used in conditions in which micro-organisms grow and 
cause problems such as, for example, in aqueous environments including 
cooling water systems, paper mill liquors, metal working fluids, 
geological drilling lubricants, polymer emulsions, and emulsion paints. 
The compound I can also be used to impregnate solid materials such as wood 
or leather or can be coated onto the surfaces thereof directly or 
incorporated into a paint, varnish or lacquer. 
The compounds I may also be used to inhibit the growth of micro-organisms 
in agricultural and horticultural environments such as living plants, 
seeds etc. 
The anti-microbial activity of the compositions of the present invention 
against both bacteria and fungi have been found to be surprisingly 
advantageous when compared to analogous compounds, for example derivatives 
disclosed in UK Patent 1113634 which are described as being isothiazoles 
but which may isomerise to give an isomeric oxime. 
As a yet further aspect of the present invention there are provided new 
compounds of the formula: 
##STR7## 
or a metal complex or salt thereof; wherein: 
A is a nitrogen or carbon atom, which may be substituted; 
B and D are, independently, oxygen or sulphur or a nitrogen or carbon atom 
which may be substituted; or 
A and/or B, and/or B and/or D may be part of a ring system; 
R is hydrogen, a hydrocarbyl group, a substituted hydrocarbyl group, an 
acyl group, a substituted acyl group or a group --COOR.sup.1 ; and 
R.sup.1 is a hydrocarbyl group 
with the proviso that B and D are not both sulphur or both oxygen, and with 
the further provisos that if the compound is other than a metal complex or 
salt thereof, 
when D is --NH-- and R is H or COCH.sub.3, A and B are not both groups 
C(CH.sub.3).sub.2 ; 
when D is --NH-- and R is H, the group A is other than .dbd.C(CH.sub.3)-- 
or .dbd.C(C.sub.6 H.sub.5)-- when the group B is .dbd.C(C.sub.6 H.sub.5)-- 
or .dbd.C(CH.sub.3)-- respectively; 
when D is --N(C.sub.6 H.sub.5)-- and R is H, the group A is other than 
--C(CH.sub.3).sub.2 -- when B is 
##STR8## 
and when D is --S-- and R is H or COC.sub.15 H.sub.31, the group A is 
other than .dbd.C(CH.sub.3)-- or .dbd.C(C.sub.6 H.sub.5)-- when B is 
.dbd.CH--. 
As a particular feature of the present invention there is provided a metal 
complex or salt of a compound of formula I subject only to the proviso 
that B and D are not both sulphur or both oxygen. 
Metal complexes or salts in accordance with this aspect of the present 
invention include ferric, cupric and zinc complexes or salts. 
New compounds of formula I include 
3-benzoyloxy-4-methylthiazol-2(3H)-thione, 
3-hydroxy-4,5,6,7-tetrahydrobenzothiazol-2(3H)-thione, 
3-acetoxy-4-methylthiazol-2(3H)-thione, 
the glutaryl bis-ester of 3-hydroxy-4-methylthiazol-2(3H)-thione, 
3-ethoxycarbonyloxy-4-methylthiazol-2(3H)-thione, 
4,5-dimethyl-3-hydroxythiazol-2(3H)-thione, 
4,5-dimethyl-3-acetoxythiazol-2(3H)-thione, 
4-ethyl-3-hydroxy-5-methylthiazol-2(3H)-thione, 
4-ethyl-3-acetoxy-5-methylthiazol-2(3H)-thione, 
4-(4-chlorophenyl)-3-hydroxythiazol-2(3H)-thione, 
3-hydroxy-5-methoxy-4-phenylthiazol-2(3H)-thione, 
3-acetoxy-4-phenylthiazol-2(3H)-thione, 
and the metal complexes or salts thereof. 
The compounds of the present invention may be prepared by known procedures 
for example as described in J.C.S. Perkin I, (1986) pages 39 to 59. 
A convenient method of preparing compounds in which the group R is hydrogen 
is by the cyclisation under basic conditions of the corresonding 
oximine-dithiocarbonate. Derivatives in which R is other than hydrogen are 
conveniently prepared by known methods from the corresponding compound in 
which R is hydrogen, for example by reaction with an acid chloride or acid 
anhydride or with an ester of chloroformic acid. The metal derivatives are 
conveniently prepared by the reaction of the compound, particularly one in 
which the group R is hydrogen, with a salt of the metal, for example a 
metal sulphate or acetate. 
The preparation of the compound, or metal complex or salt, may be effected 
in any suitable solvent such as, for example, water, a lower alkanol, an 
aqueous lower alkanol, a ketone such as acetone, N,N-dimethylformamide, 
N-methylpyrrolidone, glyme, diglyme and cellosolve. 
The reaction is preferably effected at a relatively low temperature, for 
example, not more than 80.degree. C. and especially not more than 
30.degree. C., which may be ambient temperature or below for example 
15.degree. C. If the reaction is effected at a temperature above ambient 
temperature, it is conveniently effected in acetone under reflux, that is 
at a temperature between 55.degree. and 60.degree. C. 
The desired compound can be isolated and purified using any suitable 
technique. Thus, the compound may be recrystallised from a suitable 
solvent or solvent mixture, for example from a mixture of methylene 
chloride and a low boiling petroleum ether fraction. Alternatively, the 
compound may be purified by a chromatographic technique, for example by 
flash chromatography. 
Further aspects of the present invention are described in the following 
illustrative examples. 
In the following examples, the products obtained were subjected to 
microbiostatic evaluation. The microbiological testing was effected, under 
sterile conditions throughout, as follows: 
Preparation of Inoculum 
Bacteria 
The bacterial inoculum consisted of 24 hour cultures of the organisms grown 
in Oxoid Nutrient Broth, subcultured daily and incubated at 37.degree. C. 
Fungi 
Spore suspensions of each of the test fungi were prepared as follows. To 
250 cm.sup.3 conical flasks containing well sporulating cultures of the 
organisms, growing on Oxoid Malt Extract agar, a number of sterile 3 mm 
glass beads and approximately 50 cm.sup.3 of a sterile solution of 0.01% 
v/v of polyoxyethylene (20) sorbitan mono-oleate (available from Imperial 
Chemical Industries PLC as Tween 80) (Tween is a Registered Trade Mark) in 
water were added. Each flask was swirled so that the beads removed the 
spores and the resulting suspension was poured into a sterile 100 g 
medical flat bottle containing approximately 50 cm.sup.3 of the sterile 
0.01% v/v solution of Tween 80. The suspension could be stored for up to 
four weeks at 4.degree. C. 
In the microbiological testing, the products were tested for anti-microbial 
activity against bacteria and/or fungi. The bacteria used were one or more 
of Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. 
The fungi used were one or more of Aspergillus niger, Aureobasidum 
pullulans, Cladosporium sphaerospermum, Aspergillus versicolor, and 
Chaetomium globosum. 
These test organisms will be referred to hereafter as EC, SA, PA, AN, AP, 
CS, AV and CG respectively. 
Microbiostatic evaluation 
Method A 
0.3 g of the product to be tested was dissolved in 3.0 cm.sup.3 of 
N,N-dimethylformamide to give a 10% w/v solution. 
For each of the products being tested, five bottles containing 50 cm.sup.3 
of Oxoid Malt agar and five bottles containing 50 cm.sup.3 of Oxide 
Nutrient agar were heated by steam to melt the contents. The bottles were 
cooled to 50.degree. C. and a sufficient quantity of the solution of the 
product was added to give a concentration of the product in the agar of 1 
ppm, 5 ppm, 25 ppm or 625 ppm. The lower concentrations of product were 
obtained by diluting the initial 10% w/v solution to 1% w/v or 1000 ppm 
and adding the diluted solution to the melted agar. From each bottle 
treated as described, two petri dish plates were poured and allowed to set 
overnight. 
The test organisms were surface inoculated onto the test plates by means of 
a multi-point inoculator. 
The test plates obtained from malt agar were inoculated with fungi and the 
plates were incubated at 25.degree. C. for five days. 
The test plates obtained from nutrient agar were inoculated with bacteria 
and the plates were incubated for 24 hours at 37.degree. C. 
At the end of the incubation period, the plates were assessed visually for 
growth of the micro-organisms. The concentration of the product which 
inhibited the growth of a particular micro-organism was recorded. 
Method B 
100 mg of the product to be tested was dissolver in 2 cm.sup.3 of 
N,N-dimethylformamide and the solution obtained diluted with a further 
quantity of N,N-dimethylformamide to give a product concentration of 2500 
ppm. 
To bottles containing 50 cm.sup.3 of Czapek Dox agar containing 0.5% v/v 
peptone at 50.degree. C. was added a quantity of the product solution to 
give a concentration of 500 ppm or 25 ppm of the product. In some tests, 
concentrations of 250 ppm, 50 ppm and/or 5 ppm of the product were also 
examined. From each bottle, two petri dish plates were poured and allowed 
to eat overnight. 
The test organisms were surface inoculated onto the test plates by means of 
a multi-point inoculator. Each test plate was inoculated with both 
bacteria and fungi. The plates were incubated for four days at 25.degree. 
C. 
At the end of the incubation period, the plates were assessed visually for 
growth of the micro-organisms. The concentration of the product which 
inhibited the growth of a particular micro-organism was recorded. 
In all of the following examples parts are by weight with the exception of 
solvents where parts are by volume.

EXAMPLE 1 
A compound of formula I was prepared in which the group A is 
--C(CH.sub.3).dbd., the group B is --CH.dbd., the group D is --S-- and R 
is hydrogen. 
0.885 parts of O-ethyl-5-(2-oximinopropyl)dithiocarbonate were added to 30 
parts of methylene chloride. The solution was stirred at 
0.degree.-5.degree. C. and 10 parts of aqueous 2N potassium hydroxide 
solution were added dropwise. 25 parts of methylene chloride and 25 parts 
of water were then added, the aqueous layer was separated and carefully 
acidified by the cautious addition of aqueous 2N hydrochloric acid. The 
aqueous fraction was then extracted with ethyl acetate, the extract was 
dried using anhydrous magnesium sulphate and evaporated to dryness. The 
residue was recrystallised from a mixture of ethyl acetate and petroleum 
ether (b.pt. 60.degree.-80.degree. C.) to give 
3-hydroxy-4-methylthiazol-2(3H)-thione, m.pt. 95.degree.-96.5.degree. C. 
By analysis the composition was found to be C, 32.87% wt; H, 3.2% wt; and 
N, 9.5% wt. C.sub.4 H.sub.5 NOS.sub.2 requires C, 32.6% wt; H, 3.4% wt; 
and N, 9.5% wt. 
EXAMPLE 2 
A zinc salt of the product of Example 1 was prepared. 
0.98 parts of 3-hydroxy-4-methylthiazol-2(3H)-thione were stirred in 50 
parts of water and aqueous 2N sodium hydroxide was added till a clear 
solution was achieved (pH 8). 0.96 parts of zinc sulphate heptahydrate 
were added and the reaction mixture was stirred for one hour at room 
temperature. The product was collected by filtration, washed with cold 
water and dried. The product was dissolved by boiling in 100 parts by 
volume of chloroform and the resulting solution was screened. 100 parts by 
volume of petroleum ether (b.pt. 60.degree.-80.degree. C.) were added to 
the clear filtrate to precipitate the zinc complex which was collected by 
filtration after cooling and was dried. The product had a melting point of 
268.degree.-270.degree. C. By analysis the composition was found to be C, 
26.8% wt; H, 2.2% wt; N, 7.7% wt; S, 35.2% wt and Zn, 17.7% wt. (C.sub.4 
H.sub.4 NOS.sub.2).sub.2 Zn requires C, 26.9% wt; H, 2.2% wt; N, 7.8% wt; 
S, 25.8% wt and Zn, 18.3% wt. 
EXAMPLE 3 
The benzoyl derivative of the product of Example 1 was prepared, that is R 
is COC.sub.6 H.sub.5, A, B and D are as in Example 1. 
0.735 parts of 3-hydroxy-4-methylthiazol-2(3H)-thione were stirred in 50 
parts of water and 0.84 parts of sodium hydrogen carbonate. The solution 
was screened and 0.9 parts of benzoyl chloride were added. The reaction 
mixture was stirred overnight at room temperature. A precipitate was 
formed which was separated by filtration, washed with cold water and 
recrystallised from ethanol to give 
3-benzoyloxy-4-methylthiazol-2(3H)-thione, m.pt. 100.degree.-102.degree. 
C. By analysis the composition was found to be C, 52.4% wt; H, 3.6% wt; N, 
5.6% wt and S, 25% wt. C.sub.11 H.sub.9 NO.sub.2 S.sub.2 requires C, 52.6% 
wt; H, 3.6% wt; N, 5.6% wt and S, 25.5% wt. 
EXAMPLE 4 
For comparison purposes, the following compounds were prepared. 
Compound A 
One grams of 4,5,6,7-tetrahydro-3H-1,2-benzodithiol-3-thione was mixed with 
2.2 g of anhydrous sodium acetate and 2 g of hydroxylamine hydrochloride 
in 22 cm.sup.3 of methylated spirits. The mixture was stirred under reflux 
for four hours and allowed to cool to ambient temperature overnight. The 
mixture was heated to boiling, screened and evaporated to dryness. The 
residue was washed with two 10 cm.sup.3 portions of methylated spirits at 
65.degree. C. The combined washings were evaporated to dryness and the 
solid was redissolved in methanol. A small proportion of product of 
melting point 114.degree. to 116.degree. C. crystallised. The liquid was 
separated, water was added and a precipitate was formed. The precipitate 
was filtered off and dried to give a solid of melting point 
146.degree.-148.degree. C. The infra red spectrum of this material 
contained a sharp peak at 1600 cm.sup.-1 characteristic of the oxime group 
(C.dbd.NOH), indicating that the product was 
4,5,6,7-tetrahydro-3H-1,2-benzodithiol-3-one oxime rather than the 
isomeric thione compound which is compound 10 in GB 1113634. 
Compound B 
2.5 g of 3H-1,2-benzodithiol-3-one were mixed with 5 g of anhydrous sodium 
acetate and 5 g of hydroxylamine hydrochloride in 100 cm.sup.3 of 
methylated spirits. The mixture was stirred, heated to reflux and 
maintained under reflux for ten minutes. The mixture was cooled, water was 
added forming a precipitate, the mixture was filtered and the solid was 
washed with water at 10.degree.-15.degree. C. The solid was dissolved in 
methylated spirits at 65.degree. C., the solution was screened whilst 
still hot and the solid crystallised and dried. The solid obtained had a 
melting point of 212.degree.-214.degree. C., which corresponds closely 
with the reported melting point (208.degree. C.) of 
3H-1,2-benzodithiol-3-one oxime, indicating the oxime had been obtained 
rather than the isomeric thione compound which is compound 41 of GB 
1113634. 
The compounds of Examples 1 to 3 and Compounds A and B obtained as 
described, were evaluated against a range of bacteria and fungi using 
Method A as previously described. Control for the test organisms was 
obtained at the levels set out in the Table. 
TABLE 
______________________________________ 
Com- Micro-organisms 
pound (concentrations in ppm) 
(a) EC PA SA AN AP CS AV CG 
______________________________________ 
1 25 625 125 1 1 1 1 1 
2 25 125 25 5 5 5 5 5 
3 125 NA 125 25 25 25 25 25 
A NA NA NA 125 125 125 125 125 
B NA NA NA NA 625 NA NA 625 
______________________________________ 
EXAMPLE 5 
A ferric salt of the product of Example 1 was prepared. 
0.5 parts of the compound obtained as described in Example 1 were dissolved 
in one part of ethanol. Four parts of a cold saturated aqueous solution of 
ferrous sulphate were added dropwise, with stirring, to the alcohol 
solution. The mixture was stirred at ambient temperature for 15 minutes 
and the solid product formed was obtained by filtration. The precipitate 
was washed successively with water and ethanol, boiled with chloroform, 
refiltered and dried. By analysis the product was found to be a 3:1 
complex indicating oxidation of the iron had occurred to the trivalent 
state. The product had a melting point of 220.degree. C., with 
decomposition. By analysis the composition was found to be C, 29.5% wt; H, 
2.5% wt; N, 8.3% wt and Fe, 9.7% wt. (C.sub.4 H.sub.4 NOS.sub.2).sub.3 Fe 
requires C, 29.1% wt; H, 2.4% wt; N, 8.5% wt and Fe, 11.3% wt. 
In microbiostatic evaluation using Method A, the compound provided control 
of the test organisms as follows: 
______________________________________ 
AP 25 ppm 
CS 25 ppm 
AV 25 ppm 
CG 25 ppm. 
______________________________________ 
EXAMPLE 6 
A compound of formula I was prepared in which the group A is --C(C.sub.6 
H.sub.5).dbd., the group B is --CH.dbd., the group D is --S-- and R is 
hydrogen. 
7.96 parts of phenacyl bromide and 8.334 parts of hydroxylamine 
hydrochloride were stirred overnight at ambient temperature in 75 parts of 
methanol and 25 parts of water. A further 200 parts of water were then 
added and a solid product separated which was filtered off, dried and 
recrystallised from petroleum ether (b.pt. 60.degree.-80.degree. C.) to 
yield 3.5 parts of the oxime (m.pt. 88.degree.-89.degree. C.). 
3.89 parts of the oxime, 2.9 parts of potassium ethyl xanthate and 22 parts 
of acetone were stirred overnight at ambient temperature. The reaction 
mixture was evaporated to dryness and the residue was dissolved in water. 
The resulting aqueous solution was extracted with three portions of 
diethyl ether (each portion was 50 parts by volume). The diethyl ether 
extract was dried using anhydrous magnesium sulphate and the ether was 
evaporated off to give the xanthate (3.9 parts) as a yellow oil. The oil 
was dissolved in 15 parts of ether and the solution was added to a mixture 
of 2.3 g of powder zinc chloride in 30 parts of diethyl ether which was 
being stirred at 0.degree.-5.degree. C. The mixture was stirred overnight 
and allowed to warm up to ambient temperature. The ethereal layer was 
separated by decantation and the residual syrup was digested with a 
further 30 parts of ether. 
The residue was then stirred vigorously with a mixture of 15 parts of 
methylene chloride, 15 parts of water and 15 parts of 36% aqueous 
hydrochloric acid, filtered off, and recrystallised from propan-1-ol to 
yield 0.14 parts of 3-hydroxy-4-phenylthiazol-2(3H)-thione of melting 
point 149.degree.-151.degree. C. 
In microbiostatic evaluation using Method A, the compound provided control 
of the test organism as follows: 
______________________________________ 
EC 125 ppm 
AN 125 ppm 
AP 125 ppm 
CS 25 ppm 
AV 25 ppm 
CG 25 ppm. 
______________________________________ 
EXAMPLE 7 
A compound of formula I was prepared in which the group D is --S--, R is 
hydrogen and A and B together form a cyclohexene ring. 
6.63 parts of 2-chlorocyclohexanone were used in a procedure essentially as 
described in Example 6 to form, as intermediates, the oxime (m.pt. 
62.degree.-73.degree. C.) and the xanthate (m.pt. 67.degree.-72.degree. 
C.). The final product was 
3-hydroxy-4,5,6,7-tetrahydrobenzothiazol-2)3H)-thione having a melting 
point of 111.5.degree. to 114.degree. C. 
By analysis the composition was found to be C, 44.5% wt; H, 5.0% wt; N, 
7.6% wt and S, 34.1% wt. C.sub.7 H.sub.9 ONS.sub.2 requires C, 4.9% wt; H, 
4.8% wt; N, 7.5% wt and S 34.2% wt. 
In microbiostatic evaluation using Method A, the compound provided control 
of the test organisms as follows: 
______________________________________ 
EC 25 ppm 
CA 25 ppm 
AN 125 ppm 
AP 125 ppm 
CS 125 ppm 
AV 125 ppm 
CG 125 ppm. 
______________________________________ 
EXAMPLE 8 
The acetoxy derivatives of the product of Example 1 was prepared, that is R 
is COCH.sub.3, A, B and D are as in Example 1. 
0.74 parts of 3-hydroxy-4-methylthiazol-2-(3H)-thione, 0.84 parts of sodium 
bicarbonate and 30 parts of water were stirred at 0.degree.-5.degree. C. 
while 0.52 parts of acetic anhydride were added dropwise and the reaction 
mixture was stirred at 0.degree.-5.degree. C. for a further hour. A 
precipitate was formed which was separated by filtration and 
recrystallised from aqueous methanol. 0.33 parts of 
3-acetoxy-4-methylthiazol-2(3H)-thione, of melting points 
100.degree.-101.degree. C., was obtained. 
By analysis the composition was found to be C, 38% wt; H, 3.7% wt; N, 7.3% 
wt and S, 34.0% wt. C.sub.6 H.sub.7 O.sub.2 NS.sub.2 requires C, 38.1% wt; 
H, 3.7% wt; N, 7.4% wt and S, 33.9% wt. 
in microbiostatic evaluation using Method A, the compound provided control 
of the test organisms as follows: 
______________________________________ 
EC 25 ppm 
SA 125 ppm 
AN 25 ppm 
AP 5 ppm 
CS 5 ppm 
AV 5 ppm 
CG 5 ppm. 
______________________________________ 
EXAMPLE 9 
A bis-ester of the product of Example 1 and glutaric acid was prepared. 
The procedure of Example 8 was repeated using 0.42 parts of glutaryl 
chloride rather than acetic anhydride. The glutaryl bis-ester, of melting 
point 104.5.degree.-106.5.degree. C., was obtained. 
By analysis the composition was found to be C, 39.8% wt; H, 3.8% wt; N, 
6.7% wt and S, 32.5% wt. C.sub.13 H.sub.14 N.sub.2 O.sub.4 S.sub.4 
requires C, 40.0% wt; H, 3.6% wt; N, 7.2% wt and S, 32.8% wt. 
In microbiostatic evaluation using Method A, the compound provided control 
of the test organisms as follows: 
______________________________________ 
EC 25 ppm 
SA 25 ppm 
AN 25 ppm 
AP 5 ppm 
CS 5 ppm 
AV 5 ppm 
CG 5 ppm. 
______________________________________ 
EXAMPLE 10 
A compound of formula I was prepared in which the group A is 
--C(CH.sub.3).sub.2 --, the group B is --C(NH)--, the group D is 
--N(C.sub.6 H.sub.5)-- and R is hydrogen. 
11.6 parts of acetone, 15 parts of hydroxylamine hydrochloride and 66 parts 
of water were stirred vigorously at 0.degree.-5.degree. C. while a 
solution of 11 parts of potassium cyanide in 33 parts of water was added 
over a period of 0.5 hours. The solution formed was stored at ambient 
temperature for two days and then neutralised to pH 6-7 with sodium 
acetate. The neutral solution was stored for a further five days and then 
extracted with cloroform. The chloroform extract was dried and evaporated 
to dryness. The residue was recrystallised twice from petroleum ether 
(b.pt. 60.degree.-80.degree. C.) to yield 1.4 parts of 
1-hydroxylamino-1-methylpropionitrile of melting point 
98.degree.-105.degree. C. 
The nitrile product was dissolved in 28 parts of toluene being stirred at 
ambient temperature and 1.9 parts of phenyl isothiocyanate were added. The 
reaction mixture was stirred overnight, evaporated to dryness and purified 
by flash chromatography on Kieselgel 60 (a silica gel available from Merck 
GmbH of Darmstadt, Germany). Elution was effected using petroleum ether 
(b.pt. 60.degree.-80.degree. C.) with increasing proportions of 
chloroform. 0.18 parts of 
5,5-dimethyl-1-hydroxy-4-imino-3-phenylimidazolidine-2-thione were 
obtained as an amorphous solid. 
By analysis the composition was found to be C, 56.3% wt; H, 5.4% wt; N, 
16.5% wt and S, 13.0% wt. C.sub.11 H.sub.13 N.sub.3 OS requires C, 56.1% 
wt; 5.5% wt; N, 17.9% wt and S, 13.6% wt. 
In microbiostatic evaluation using Method A, the compound provided control 
of the test organisms as follows: 
______________________________________ 
AN 25 ppm 
AP 25 ppm 
CS 25 ppm 
AV 25 ppm 
CG 25 ppm. 
______________________________________ 
EXAMPLE 11 
A compound of formula I, and the cupric complex thereof, were prepared in 
which the group A is a spirocyclohexyl group 
##STR9## 
and B, D and R are as in Example 10. 
The procedure of Example 10 was repeated using cyclohexanone. The product 
obtained was converted to the 2:1 cupric complex by reaction with cupric 
sulphate using the procedure of Example 2. 
By analysis the composition was found to be N, 12.9% wt and Cu, 8.9% wt. 
(C.sub.14 H.sub.16 N.sub.3 OS).sub.2 Cu.sub.3 H.sub.2 O requires N, 12.6% 
wt and Cu, 9.4% wt. 
In mircobiostatic evaluation using Method A, the compound provided control 
of the test organisms as follows: 
______________________________________ 
AN 25 ppm 
AP 25 ppm 
CS 25 ppm 
AV 25 ppm 
CG 25 ppm. 
______________________________________ 
EXAMPLE 12 
A compound of formula I was prepared in which the group A is 
--C(CH.sub.3).dbd., the group B is --C(C.sub.6 H.sub.5).dbd., the group D 
is --NH-- and R is hydrogen. 
15.1 parts of C-phenylglycine, 100 parts of acetic anhydride and 100 parts 
of pyridine were heated a t 90.degree. C. until all evolution of carbon 
dioxide had ceased. The reaction mixture was evaporated to give an oil. 
300 parts of toluene were added and this mixture was evaporated to give a 
solid residue. 
The solid residue was stirred under reflux with 200 parts of aqueous 5N 
hydrochloric acid. The resulting solution was screened and evaporated to 
dryness. The solid residue was recrystallised from ethanol to yield 11.65 
parts of alpha-acetylbenzylamine hydrochloride, of melting point 
204.5.degree.-206.degree. C. 
4.65 parts of this hydrochloride and 3.5 parts of hydroxylamine 
hydrochloride were stirred in 25 parts of water. The mixture was stirred 
whilst being boiled and 8.25 parts of sodium acetate dissolved in 20 parts 
of water were added. The reaction mixture was stirred overnight whilst 
being allowed to cool to room temperature. A further 1.75 parts of 
hydroxylamine hydrochloride and 4.15 parts of sodium acetate dissolved in 
10 parts of water were added, the reaction mixture was then cooled to 
0.degree.-5.degree. C. A precipitate was formed which was separated by 
filtration and dissolved in 40 parts of water containing one part of 
sodium carbonate. This solution was extracted with chloroform and the 
chloroform was evaporated to give 1.99 parts of an oxime of melting point 
73.degree.-74.5.degree. C. 
1.64 parts of the oxime and 2.8 parts of triethylamine were dissolved in 33 
parts of tetrahydrofuran (solution A). 0.8 parts of thiophosgene were 
dissolved in 33 parts of tetrahydrofuran (solution B). Solutions A and B 
were added simultaneously over a period of one hour to 133 parts of 
tetrahydrofuran which were being stirred at -65.degree. C. The reaction 
mixture was allowed to warm up to 0.degree. C. overnight and was then 
screened and evaporated to dryness. The solid was recrystallised from 
ethanol to give 0.27 parts of 
1-hydroxy-5-methyl-4-phenylimidazoline-2-thione having a melting point of 
202.degree. C. 
By analysis the compound was found to contain 12.9% wt of nitrogen. 
C.sub.10 H.sub.10 N.sub.2 OS requires 13.6% wt of nitrogen. 
In microbiostatic evaluation using Method B, the compound provided control 
of the test organisms as follows: 
______________________________________ 
EC 500 ppm 
SA 500 ppm 
AN 500 ppm 
AP 25 ppm 
CS 500 ppm 
AV 25 ppm 
CG 25 ppm. 
______________________________________ 
EXAMPLE 13 
The ethoxycarbonyl derivative of the product of Example 1 was prepared, 
that is R is C.sub.2 H.sub.5 OCO, A, B and D are in Example 1. 
0.98 parts of the product of Example 1 were dissolved in 20 parts of 
toluene and treated with 0.6 parts of triethylamine and 0.72 parts of 
ethyl chloroformate at ambient temperature. Further portions of 
triethylamine and ethyl chloroformate were added at intervals until no 
more of the starting material was present, as indicated by thin layer 
chromatography. The reaction mixture was screened, evaporated to dryness 
and the product purified by flash chromatography (as in Example 10) to 
obtain 3-ethoxycarbonyloxy-4-methylthiazol-2(3H)-thione as a semi-solid 
gum. 
By analysis the composition was found to be C, 37.7% wt; H, 4.3% wt; N, 
6.4% and S, 31.3% wt. C.sub.7 H.sub.9 NO.sub.3 S.sub.2 requires C, 38.4% 
wt; H, 4.1% wt; N, 6.4% wt and S, 29.2% wt. 
In microbiostatic evaluation using Method B, the compound provided control 
of the test organisms as follows: 
______________________________________ 
EC 25 ppm 
PA 500 ppm 
SA 50 ppm 
AN 25 ppm 
AP 5 ppm 
CS 25 ppm 
AV 25 ppm 
CG 5 ppm. 
______________________________________ 
EXAMPLE 14 
A compound of formula I was prepared in which the group A is 
--C(CH.sub.3).dbd., the group B is --C(CH.sub.3).dbd., the group D is 
--S-- and R is hydrogen. 
53.25 parts of 3-chloro-2-butanone were added dropwise over a period of 15 
minutes to a rapidly stirred slurry of 52.12 parts of hydroxylamine 
hydrochloride in 50 parts of water at ambient temperature. The mixture was 
stirred for one hour at ambient temperature and was then cooled to 
0.degree.-5.degree. C. The mixture at 0.degree.-5.degree. C. was 
neutralised with sodium carbonate solution and stirred for a further hour 
whilst warming up to ambient temperature. The solution was contacted with 
diethyl ether and the ether extract was dried and evaporated to dryness to 
give 51 parts of the oxime as a pale yellow oil (Proton magnetic resonance 
using CDCl.sub.3 as solvent an d tetramethylsilane as internal reference 
showed a doublet peak at a delta value of 1.6 ppm, a singlet peak at a 
delta value of 1.9 ppm, a quadruplet peak at a delta value of 4.6 ppm and 
a broad singlet peak at a delta value of 9 ppm). 
12.15 parts of the oxime were reacted with potassium ethyl xanthate using 
the procedure as generally described in Example 6 to obtain a solid 
xanthate having a melting point of 62.degree.-64.degree. C. 
The xanthate was cyclised using dilute potassium hydroxide, the procedure 
being generally as described in Example 1. 
4,5-dimethyl-3-hydroxythiazol-2(3H)-thione was isolated as a white 
crystalline solid. 
By analysis the compound was found to contain 8.3% wt of nitrogen. C.sub.5 
H.sub.7 NOS.sub.2 requires 8.7% wt of nitrogen. The proton magnetic 
resonance spectrum, obtained as described previously, showed singlets at 
delta values of 2.18 and 2.2 ppm. 
In microbiostatic evaluation using Method B, the compound provided control 
of the test organisms as follows: 
______________________________________ 
EC 25 ppm 
SA 500 ppm 
AN 25 ppm 
AP 25 ppm 
CS 5 ppm 
AV 5 ppm 
CG 5 ppm. 
______________________________________ 
EXAMPLE 15 
The acetoxy derivative of the product of Example 14 was prepared, that is R 
is COCH.sub.3, A, B and D are as in Example 14. 
The procedure of Example 8 was repeated with the exception that 0.8 parts 
of the product of Example 14 were used. 
4,5-dimethyl-3-acetoxythiazol-2(3H)-thione was obtained as a white solid. 
By analysis the composition was found to be C, 41.3% wt; H, 4.5% wt; N, 
6.9% wt and S, 32.1% wt. C.sub.7 H.sub.9 NO.sub.2 S.sub.2 requires C, 
41.3% wt; H, 4.4% wt; N, 6.9% wt and S, 31.5% wt. 
in microbiostatic evaluation using Method B, the compound provided control 
of the test organisms follows: 
______________________________________ 
EC 25 ppm 
AN 25 ppm 
AP 25 ppm 
AV 25 ppm 
CG 25 ppm. 
______________________________________ 
EXAMPLE 16 
The cupric complex of the compound of Example 14 was prepared. 
0.99 parts of cupric acetate dissolved in 50 parts of methanol were added 
with stirring to a stirred solution of 1.61 parts of 
4,5-dimethyl-3-hydroxythiazol-2(3H)-thione in 50 parts of methanol at 
ambient temperature. The mixture was stirred at ambient temperature for 
four hours, a green precipitate, of the 2:1 cupric complex, was isolated 
by filtration and then washed with water at 10.degree.-15.degree. C. and 
dried. The solid had a melting point of 250.degree.-252.degree. C. 
By analysis the composition was found to be C 31.0% wt; H, 3.1% wt; N, 7.1% 
wt and Cu, 15.7% wt. (C.sub.5 H.sub.7 NOS.sub.2).sub.2 Cu requires C, 
31.3% wt; H, 3.1% wt; N, 7.3% wt and Cu, 16.6% wt. 
In microbiostatic evaluation using Method B, the compound provided control 
of the test organisms as follows: 
______________________________________ 
AP 25 ppm 
AV 25 ppm 
CG 25 ppm. 
______________________________________ 
EXAMPLE 17 
The zinc complex of the compound of Example 14 was prepared. 
1.2 parts of 4,5-dimethyl-3-hydroxythiazol-2(3H)-thione were reacted with 
zinc acetate in methanol using the procedure of Example 16. The 2:1 zinc 
complex was obtained as a white solid of melting point 
235.degree.-238.degree. C. 
By analysis the composition was found to be C, 31.3% wt; H, 3.1% wt; N, 
7.1% wt and Zn, 16.6% wt. (C.sub.5 H.sub.6 NOS.sub.2).sub.2 Zn requires C, 
31.2% wt; H, 3.1% wt; N, 7.3% wt and Zn, 16.9% wt. 
In microbiostatic evaluation using Method B, the compound provided control 
of the test organisms as follows: 
______________________________________ 
EC 25 ppm 
SA 500 ppm 
AN 25 ppm 
AP 25 ppm 
CS 25 ppm 
AV 25 ppm 
CG 25 ppm. 
______________________________________ 
EXAMPLE 18 
A compound of formula I was prepared in which the group A is --C(C.sub.2 
H.sub.5).dbd., B is --C(CH.sub.3).dbd., D is --S-- and R is hydrogen. 
33 parts of 2-bromopentan-3-one were treated as described in Example 14 to 
obtain the oxime and the xanthate as intermediates and finally to obtain, 
as the final product, 4-ethyl-3-hydroxy-5-methylthiazol-2(3H)-thione as a 
solid of melting point 87.degree.-89.degree. C. 
By analysis the composition was found to be C 41.3% wt; H, 5.6% wt; N, 8.1% 
wt and S, 36.2% wt. C.sub.6 H.sub.9 NOS.sub.2 requires C, 41.1% wt; H, 
5.1% wt; N, 8.0% wt and S, 36.6% wt. 
In microbiostatic evaluation using Method A, the compound provided control 
of the test organisms as follows: 
______________________________________ 
EC 25 ppm 
AN 125 ppm 
AP 25 ppm 
CS 125 ppm 
AV 25 ppm 
CG 5 ppm. 
______________________________________ 
EXAMPLE 19 
The acetoxy derivative of the product of Example 18 was prepared, that is R 
is COCH.sub.3, A, B and D are as in Example 18. 
The procedure of Example 8 was repeated with the exception that 0.82 parts 
of the product of Example 18 was used. 
By analysis the composition was found to be C, 44% wt; H, 5.2% wt; N, 6.5% 
wt and S, 29.5% wt. C.sub.8 H.sub.11 NO.sub.2 S.sub.2 requires C, 44.2% 
wt; H, 5.1% wt; N, 6.5% wt and S, 29.5% wt. 
In microbiostatic evaluation using Method B, the compound provided control 
of the test organisms as follows: 
______________________________________ 
EC 25 ppm 
AN 500 ppm 
AP 500 ppm 
CS 500 ppm 
AV 500 ppm 
CG 500 ppm. 
______________________________________ 
EXAMPLE 20 
The zinc complex of the compound of Example 18 was prepared. 
The procedure was as described in Example 17 with the exception that 1.35 
parts of the compound of Example 18 were used. The solid zinc complex had 
a melting point of 204.degree.-210.degree. C. 
By analysis the composition was found to be C, 35% wt. H, 4.0% wt; N, 6.8% 
wt; S, 39.4% wt and Zn 15.6% wt. (C.sub.6 H.sub.8 NOS.sub.2).sub.2 Zn 
requires C, 34.9% wt; H, 3.9% wt; N, 6.8% wt; S, 31% wt and Zn, 15.3% wt. 
In microbiostatic evaluation using Method B, the compound provided control 
of the test organisms as follows: 
______________________________________ 
EC 25 ppm 
AN 500 ppm 
AP 500 ppm 
CS 500 ppm 
AV 500 ppm 
CG 25 ppm. 
______________________________________ 
EXAMPLE 21 
A compound of formula I was prepared in which the group A is --C(C.sub.6 
H.sub.4 Cl).dbd., B is --CH.dbd., D is --S-- and R is hydrogen. 
The procedure of Example 6 was repeated with the exception that 
4-chlorophenacylbromide was used rather than phenacylbromide. The final 
product was 4(4-chlorophenacyl)-3-hydroxythiazol-2(3H)-thione, which was 
obtained as a white solid. 
By analysis the composition was found to be N, 5.2% wt and S, 25.6% wt. 
C.sub.9 H.sub.6 ClNOS.sub.2 requires N, 5.7% wt and S, 26.3% wt. 
In microbiostatic evaluation using Method A, the compound provided control 
of the test organisms as follows: 
______________________________________ 
EC 25 ppm 
SA 125 ppm 
AN 125 ppm 
AP 125 ppm 
CS 125 ppm 
AV 125 ppm 
CG 125 ppm. 
______________________________________ 
EXAMPLE 22 
A compound of formula I was prepared in which the group A is --C(C.sub.6 
H.sub.6).dbd., B is --C(CH.sub.3).dbd., D is --S-- and R is hydrogen. 
The procedure of Example 6 was repeated with the exception that 
w-chloro-w-methylacetophenone was used rather than phenacylbromide to 
obtain 3-hydroxy-5-methyl-4-phenylthiazol-2(3H)-thione. The proton 
magnetic resonance spectrum, obtained as described in Example 14, showed 
singlets at delta values of 2.05 ppm and 7.3 ppm. In microbiostatic 
evaluation using Method A, the compound provided control of the test 
organisms as follows: 
______________________________________ 
EC 125 ppm 
SA 125 ppm 
AN 125 ppm 
AP 5 ppm 
CS 25 ppm 
AV 25 ppm 
CG 5 ppm. 
______________________________________ 
EXAMPLE 23 
The acetoxy derivative of the product of Example 6 was prepared, that is R 
is COCH.sub.3, A, B and D are as in Example 6. 
The procedure of Example 8 was repeated with the exception that one part of 
the product of Example 6 was used. 3-acetoxy-4-phenylthiazol-2(3H)-thione 
was obtained as a white solid. The proton magnetic resonance spectrum, 
obtained as described in Example 14, showed singlets at delta values of 
2.1 ppm, 6.45 ppm and 7.35 ppm. 
By analysis the compound was found to contain 5.6% wt of nitrogen. C.sub.11 
H.sub.9 NO.sub.2 S.sub.2 requires 5.6% of nitrogen. 
In microbiostatic evaluation using Method B, the compound provided control 
of the test organisms as follows: 
______________________________________ 
EC 25 ppm 
SA 500 ppm 
AN 500 ppm 
AP 500 ppm 
AP 500 ppm 
CS 500 ppm 
AV 500 ppm 
CG 25 ppm. 
______________________________________