Process for preparing tetrahydropyrimidines

Substituted 2, 3, 4, 5-tetrahydropyridimines (THP) ##STR1## are prepared as follows: (1) The reaction of a carbonyl compound (ketone or aldehyde) with (NH.sub.3 or NH.sub.4 OH) and a sulfur-containing catalyst. PA1 (2) The reaction of an .alpha., .beta.-unsaturated ketone and a carbonyl compound and NH.sub.3 (or NH.sub.4 OH) without a catalyst. PA1 (3) Reaction of an .alpha., .beta.-unsaturated ketone, a 1-amino-alcohol and NH.sub.3 (or NH.sub.4 OH) without a catalyst. The compositions of this invention react with carbon disulfide to form xanthates, can be isomerized, converted to pyridines, etc. Thp and derivatives of this invention are useful as biocides, anti-oxidants, oxygen scavengers, corrosion inhibitors, etc.

This invention relates to tetrahydropyrimidines (THP), to the preparation 
thereof with or without novel catalysts; uses thereof; and to derivatives 
thereof. 
THP is prepared by the following procedures: 
I 
Reaction of a carbonyl compound (aldehyde or ketone) with ammonia according 
to the general reaction 
##STR2## 
II 
Reaction of an .alpha., .beta. unsaturated ketone with ammonia and a 
carbonyl compound (aldehyde or ketone) according to the general reaction 
##STR3## 
III 
Reaction of an unsaturated carbonyl compound (aldehyde or ketone) with a 
1-aminoalcohol and ammonia according to the general reaction 
##STR4## 
R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5 and R.sub.6, which may be the 
same or different, are hydrogen or substituted group such as alkyl, aryl, 
cycloalkyl, alkaryl, aralkyl, heterocyclic, substituted derivatives 
thereof, etc. In addition R groups may be joined in a cyclic configuration 
which makes the THP structure a part of the substituted group. 
Alkyl includes methyl, ethyl, propyl, butyl, amyl, hexyl, heptyl, octyl, 
nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, 
hexadecyl, heptadecyl, octadecyl, escosyl, docosyl, etc. for example 
having about 1-25 or more carbons such as from about 1-18 carbons, but 
preferably about 1-12 carbons. The term "alkyl" also includes isomers of 
the straight chain where branching occurs. 
Cycloalkyl includes cyclopentyl, cyclohexyl, etc. and derivatives thereof 
such as alkyl cyclohexyl, dialkyl-cyclohexyl, etc. 
Aryl, alkaryl and aralkyl include phenyl, alkylphenyl, polyalkylphenyl, 
chlorophenyl, alkoxyphenyl, naphthyl, alkylnaphthyl, etc., benzyl, 
substituted benzyl, etc. 
The joining of the R groups into a ring structure include those structures 
derived from reactants of the general formula 
EQU (CH.sub.2).sub.n C = O 
such as cyclohexanone, cyclopentanone, substituted derivatives thereof such 
as alkyl-cyclohexanone, dialkyl-cyclohexanone. 
In general, the catalyst employed herein is a sulfur or a sulfur-containing 
compound. The preferred catalyst is carbon disulfide or the reaction 
product of CS.sub.2 with an amine to yield an xanthate of the general 
formula 
##STR5## 
particularly as a salt thereof. 
The groups substituted on the nitrogen of the xanthate can vary widely for 
example, alkyl, cycloalkyl, aryl, alkaryl, aralkyl, heterocyclic, etc. 
The salt moiety can also vary widely for example alkali metal Na, K, Li, 
etc., alkali earth, Ca, etc., metal, NH.sub.4, amine, etc. 
In the preferred embodiment, CS.sub.2 forms an xanthate inner salt with the 
tetrahydropyrimidines of this invention such as 
##STR6## 
represents the tetrahydropyrimidine ring having a charged amino group for 
example 
##STR7## 
The catalyst is employed in a concentration of at least about 0.05 mole 
percent of the reactants, such as from about 0.05-3.0 mole percent, for 
example from about 0.1 to 2.0 mole percent, but preferably from about 0.3 
to 0.5 mole percent. Larger amounts can be employed, if desired, but there 
is generally no advantage in doing so. 
In general, the reaction, which is mildly exothermic, is carried out at 
ambient temperatures. Although elevated temperatures can be employed, the 
reaction is generally carried out at room temperature. Although elevated 
pressures can be employed such as from 0-100 psi, the reaction can be 
carried out at atmospheric pressure. 
The following equations illustrate the preparation of derivatives of the 
compositions of this invention: 
The substituted 2, 3, 4, 5 tetrahydropyrimidines of this invention are 
useful as intermediate for the preparation of N-dithiocarboxylates. 
Reaction of the substituted 2, 3, 4, 5 tetrahydropyrimidines with carbon 
disulfide yielded 1:1 adducts. 
##STR8## 
These adducts are efficient corrosion inhibitors in acid systems. 
2. The tetrahydropyrimidinines can be isomerized from 2, 3, 4, 5 to 1, 4, 
5, 6 tetrahydropyrimidines 
##STR9## 
In this reaction it is required that R.sub.6 by hydrogen. These are useful 
as corrosion inhibitors. 
3. The tetrahydropyrimidines can be converted to substituted pyridines. 
##STR10## 
For this reaction, the 2 position contains at least 1 hydrogen and one of 
the groups attached to carbon 4 has at least a methylene group. These are 
useful as bactericides.

The following examples are presented for purpose of illustration and not of 
limitation. 
EXAMPLE 1 
4.4.6 - Trimethyl - 2,3,4,5 - tetrahydropyrimidine 
A sample of 392 g. of mesityloxide and 800 cc. of 28% aq. ammonium 
hydroxide were stirred in a closed reaction vessel for 3 hours. The 
mixture was allowed to stand for 15 hours at ambient temperature. To the 
solution was added over a 1/2 hour period 300 cc. of an aq. 37% solution 
of formaldehyde. The temperature of the reaction mixture rose to 
64.degree. C. during the addition. After the addition was completed the 
mixture was stirred for 3 hours. Distillation of the reaction product 
yielded 419 g. (84% of theory) of 4.4.6 - trimethyl - 2,3,4,5 
tetrahydropyrimidine as a colorless liquid; b.sub.15 62-65.degree. C.; 
infrared spectrum, 3.08 m .mu., weak (N--H) and 6.02 m .mu., strong 
(C.dbd.N); nuclear magnetic resonance spectrum, .tau. in ppm, no solvent; 
5.62 multiplet 2H; 8.14 multiplet + singlet 5H; 9.02 singlet 6H; and 7.72 
singlet 1H. 
Anal. Calc.ed for C.sub.7 H.sub.14 N.sub.2 : N, 22.22. Found: N, 21.89. 
EXAMPLE 2 
2.4.4.6 - Tetramethyl - 2,3,4,5 - tetrahydropyrimidine 
In a manner as described in example 1, a sample of 98 g. of mesityloxide; 
200 cc. of 28% aq. ammonium hydroxide; and 50 g. of acetaldehyde yielded 
120.5 g. (86% of theory) of 2.4.4.6 -tetramethyl - 2,3,4,5 
tetrahydropyrimidine as a colorless liquid; b.sub.15 68-72.degree. C.; 
infrared spectrum 3.06 m .mu. weak (N--H) and 6.02 m .mu. strong (C--N); 
nuclear magnetic resonance spectrum, .tau. in ppm, no solvent; 5.68 
multiplet 1H; 8.15 singlet 3H, 8.20 singlet 2H; 8.77 doublet 3H; 8.93 
singlet 3H; 9.04 singlet 3H; and 8.41 singlet 1H. 
Anal. Calc.ed for C.sub.8 H.sub.16 N.sub.2 : N, 20.00. Found: N, 19.89. 
EXAMPLE 3 
2 - n - Propyl - 4.4.6 - trimethyl - 2,3,4,5 - tetrahydropyrimidine 
In a 1 pint pressure reactor was placed 98 g. of mesityloxide and 72 g. of 
butyraldehyde. Over a 5 hour period a sample of 50.6 g. of ammonia gas was 
introduced at such a rate that the pressure did not rise above 56 psi, 
After the addition was completed, stirring was continued for 17 more 
hours. The reaction product was dissolved in benzene and the aqueous 
layer, 34 cc. was separated. The benzene layer was evaporated under 
diminished pressure to yield 178.9 g. of an oil. Distillation of the oil 
under diminished pressure yielded 141 g. (84% of theory) of 
2-n-propyl-4.4.6 - trimethyl -2,3,4,5 - tetrahydropyrimidine, b.sub.20 
78-90.degree. C.; infrared spectrum 3.06 m .mu. weak (N--H) and 6.01 m 
.mu. strong (C.dbd.N) 
Anal. Calc.ed for C.sub.10 H.sub.20 N.sub.2 : N, 16.65. Found: N, 16.53. 
In a fashion as described in example 3, the following 2-substituted 4.4.6 
-trimethyl - 2,3,4,5 tetrahydropyrimidines listed in Table I were prepared 
from mesityloxide, ammonia gas and an aldehyde. 
Table I 
__________________________________________________________________________ 
2-Substituted - 4.4.6 - trimethyl - 2,3,4,5 - tetrahydropyrimidines from 
mesityloxide, ammonia 
gas and an aldehyde 
Ex- Mesityl- Alde- Reaction 
Maxi- 2-substi- 
Yield 
ample 
oxide hyde 
Ammonia 
time mum pres- 
ent in 
of 
no. grams 
Aldehyde grams 
grams 
hours 
sure psi 
Product 
theory 
__________________________________________________________________________ 
4 98 n-heptaldehyde 
114 44 21 60 n-hexyl 
90 
5 98 2-ethylbutyraldehyde 
100 49 20 55 3-n-pentyl 
90 
6 98 benzaldehyde 
106 47 21 60 phenyl 
96 
7 98 2-ethylhexanal 
128 43 24 65 3-n-heptyl 
88 
8 98 nonylaldehyde 
142 44 24 65 n-octyl 
88 
__________________________________________________________________________ 
EXAMPLE 9 
2.4.4.6 - Tetramethyl - 2,3,4,5 - tetrahydropyrimidine 
A sample of 98 grams of mesityloxide and 100 cc. of 28% ammonium hydroxide 
were stirred for 18 hours. To the mixture was added 61 grams of 
1-amino-ethanol (acetaldehyde-ammonia) and the mixture was heated to 
50.degree. C. After all the solid was dissolved, the mixture was allowed 
to cool to room temperature. Distillation of the product yielded 128 g. 
(91% of theory) of 2.4.4.6-tetramethyl - 2,3,4,5-tetrahydropyrimidine 
identical to the product described in example 2. 
EXAMPLE 10 
2.2.4.4.6 - Pentamethyl - 2,3,4,5 - tetrahydropyrimidine 
In a pressure reactor was placed a mixture of 196 grams of mesityloxide and 
137 grams of acetone. Over a 5 hour period 88 grams of ammonia gas was 
introduced at such a rate that the autogeneous pressure did not exceed 70 
psi. After the addition was completed, the mixture was stirred for 18 more 
hours. The resulting reaction product was distilled under diminished 
pressure and the product b.sub.20 63-66.degree. C., 265 g. (86% of theory) 
of 2.2.4.4.6 - pentamethyl - 2,3,4,5 - tetrahydropyrimidine was collected; 
infrared spectrum 3.06 m .mu. weak (N--H) and 6.02 m .mu. strong (C--N); 
nuclear magnetic resonance spectrum .tau. in ppm, no solvent, 8.12 singlet 
and 8.16 singlet 5H; 8.72 singlet 6H; and 8.96 singlet 6H. 
Anal. Calc.ed for C.sub.9 H.sub.18 N.sub.2 : N, 18.18. Found: N, ;b 17.97. 
As described in example 10, the following 2.2 disubstituted 4.4.6 trimethyl 
- 2,3,4,5 tetrahydropyrimidines, listed in Table II were prepared from 
mesityloxide, ammonia gas and a ketone. 
Table II 
__________________________________________________________________________ 
2.2.-Disubstituted 4.4.6 - trimethyl - 2,3,4,5 - tetrahydro- 
pyrimidines from mesityloxide, ammonia gas a ketone. 
Mesi- Am- 2.2 boil- 
Ni- % 
tyl- Ke- mon- 
disub- 
ing tro- Yield 
Ex. 
oxide tone 
ia stitu- 
point 
gen 
Anal. 
of 
No. 
grams 
Ketone 
grams 
grams 
ents .degree. C. 
Cal. 
Found 
theory 
__________________________________________________________________________ 
11 98 methylethyl 
72 34 methyl 
b.sub.0.8 = 
ketone ethyl 
38-40 
16.65 
16.50 
84 
12 83 cyclo- 
83 51 penta- 
b.sub.1.0 = 
hexanone methy- 
78-80 
14.43 
14.33 
84 
lene 
13 98 4-methyl- 
112 44 5'methyl 
b.sub.20 = 
cyclohex- penta- 
115-121 
13.46 
13.51 
86 
amine methy- 
lene 
__________________________________________________________________________ 
EXAMPLE 14 
2.2 Pentamethylene - 4.4.6 - trimethyl - 2,3,4,5 - tetrahydropyrimidine 
A mixture of 98 grams of mesityloxide; 98 grams of cyclohexanone, 100 grams 
of methanol and 200 cc. of 28% aq. ammonium hydroxide was stirred for 19 
hours at ambient temperature. The mixture was evaporated under diminished 
pressure and the resulting 178 grams of product distilled under diminished 
pressure to yield 164 grams (84.5% of theory) of 2.2-pentamethylene - 
4.4.6 -trimethyl- 2,3,4,5 - tetrahydropyrimidine identical to the product 
described in example 12; infrared spectrum, 3.04 m .mu. N--H (weak) and 
6.02 m .mu. C.dbd.N (strong); nuclear magnetic resonance spectrum; .tau. 
in ppm, no solvent; 8.12 singlet 3H; 8.18 singlet 2H; 8.47 broad singlet 
10H; and 8.97 singlet 6H. 
Anal. Calc.ed for C.sub.12 H.sub.22 N.sub.2 : N, 14.43. Found: N, 14.30. 
EXAMPLE 15 
2.4-Dipentamethylene-5,6-tetramethylene-2,3,4,5-tetrahydropyrimidine 
To a stirred mixture of 98 grams of cyclohexanone and 93 grams of 28% aq. 
ammonium hydroxide was added 0.7 cc. of carbon disulfide. The mixture was 
stirred for 15 more minutes and an additional 0.7 cc. of carbondisulfide 
was added. Stirring was continued for 16 more hours. The mixture was 
evaporated under diminished pressure and the residue distilled from solid 
potassium hydroxide to yield 73 grams (80% of theory) of 
2.4-dipentamethylene-5,6-tetramethylene-2,3,4,5-tetrahydropyrimidine as a 
viscous liquid b.sub.0.8 = 186.degree.-188.degree. C., which slowly 
solidified upon standing; infrared spectrum 3.02 m .mu. weak (N--H) and 
6.02 m .mu. strong (C.dbd.N). 
Anal. Calc.ed for C.sub.18 H.sub.30 N.sub.2 : N, 10.20. Found: N, 9.88. 
As described in example 15, 
2.4-Dipentamethylene-5,6-tetramethylene-2,3,4,5-tetrahydropyrimidine was 
produced from cyclohexanone, aq. 28% ammonium hydroxide and carbon 
disulfide as the catalyst, in varied ratios of reactants. The results are 
collected in Table III. 
Table III 
______________________________________ 
Formation of 2.4 - Dipentamethylene - 5.6 - tetramethylene - 
2,3,4,5 - tetrahydropyrimidine from cyclohexanone, 
28% aq. ammonium hydroxide and carbon disulfide 
28% aq. 
Cyclohex- Ammonium Carbon % Yield 
Ex. anone hydroxide disulfide 
Reaction 
of 
No. grams grams grams time-hrs. 
theory 
______________________________________ 
16 49 72 -- 18 6 
17 49 20 0.6 18 53 
18 49 30 1.2 18 66 
19 49 40 1.2 18 76 
20 49 36 1.2 18 76 
21 49 45 0.8 18 78 
22 49 20 0.6 + 0.6* 
18 80 
23 49 72 0.4 + 0.3* 
18 81 
______________________________________ 
*Catalyst added in two portions at 15 minutes interval. 
EXAMPLE 24 
Trimethyl 2.4-Dipentamethylene-5,6-tetramethylene-2,3,4,5 
tetrahydropyrimidine 
In a pressure reactor was placed 112 grams of 3-methylcyclohexanone and 2 
grams of carbon disulfide. To the mixture was added over a 4 hour period 
14 grams of ammonia gas. After the addition was completed the mixture was 
stirred for 18 more hours at ambient temperature. The aqueous phase which 
separated, 17.8 cc., was removed and the product distilled over potassium 
hydroxide under diminished pressure. The trimethyl 
2.4-dipentamethylene-5.6-tetramethylene-2,3,4,5-tetrahydropyrimidine was 
collected as 76.5 g. (73% of theory) of a very viscous liquid. 
EXAMPLE 25 
Carbon disulfide adduct of 
2.4-Dipentamethylene-5.6-tetramethylene-2,3,4,5-tetrahydropyrimidine 
A sample of 27.4 grams of 
2.4-dipentamethylene-5,6-tetramethylene-2,3,4,5-tetrahydropyrimidine was 
dissolved in 250 cc. of ether. To the solution was added 10 grams of 
carbon disulfide and the mixture was allowed to stand for 16 hours. The 
bright yellow solid which precipitated was filtered off and washed one 
time with ether. The product was air dried to yield 34.5 grams (98.5% of 
theory) of the carbon disulfide adduct of 
2.4-dipentamethylene-5.6-tetramethylene 2,3,4,5-tetrahydropyrimidine, m.p. 
122.degree.-124.degree. C. 
Anal. Calc.ed for C.sub.19 H.sub.30 N.sub.2 S.sub.2 : N, 8.0 : S, 17.8. 
Found: N, 8.1 : S, 18.3. 
EXAMPLE 26 
2.4-Dipentamethylene-5.6-tetramethylene-2,3,4,5-tetrahydropyrimidine 
In a pressure reactor was placed 49 grams of cyclohexanone and 1 gram of 
carbon disulfide. Over a 41/2 hour period 7.5 grams of ammonia gas was 
introduced. After the addition was completed the mixture was stirred for 3 
more hours. The aqueous layer (8.1 cc.) was separated by extraction of the 
product in ether. The ethereal solution was evaporated and the resulting 
product distilled under diminished pressure to yield 40 grams (87.5% of 
theory) of 
2.4-dipentamethylene-5.6-trimethylene-2,3,4,5-tetrahydropyrimidine, 
identical to product described in example 15. 
EXAMPLE 27 
Carbon disulfide adduct of 
2.4-Ditetramethyne-5.6-trimethylene-2,3,4,5-tetrahydropyrimidine 
Into a mixture of 84 grams of cyclopentanone, 2 grams of carbon disulfide 
and 50 grams of methanol was introduced over a 3-1/2 hour period 18.2 
grams of ammonia gas. After the addition was completed the mixture was 
stirred for 15 more hours at ambient temperature. The solvent was removed 
under diminished pressure and the resulting product was distilled under 
diminished pressure. A sample of 18 grams of the distilled product was 
dissolved in 100 cc. of ether and 40 grams of carbon disulfide was added. 
The mixture was allowed to stand at room temperature for 1 hour and the 
solid which precipitated was filtered off and washed with ether. The 
yellow solid was air dried to yield 9.0 grams of the carbon disulfide 
adduct of 
2.4-ditetramethylene-5.6-trimethylene-2,3,4,5-tetrahydropyrimidine, m.p. 
105.degree.-108.degree. C. 
Anal. Calc.ed for C.sub.16 H.sub.24 N.sub.2 S.sub.2 : N, 9.1; S, 20.8. 
Found: N, 9.35; S, 23.0. 
EXAMPLE 28 
2.2.4.4.6-Pentamethyl-2,3,4,5-tetrahydropyrimidine 
In a pressure reactor was placed 174 grams of acetone and 1.54 grams of the 
carbon disulfide adduct 
2.4-dipentamethylene-5,6-tetramethylene-2,3,4,5-tetrahydropyrimidine, 
described in example 25. To the mixture was added 30.4 grams of ammonia 
gas over a 4 hour period at such a rate that the autogeneous pressure did 
not exceed 60 psi. After the addition was completed the mixture was 
stirred for 70 more hours. Distillation yielded 90 grams (59% of theory) 
of 2.2.4.4.6-pentamethyl-2,3,4,5-tetrahydropyrimidine identical to the 
product described in example 10. 
In a fashion as described in example 28, 2.2.4.4.6-Pentamethyl 
2,3,4,5-tetrahydropyrimidine was prepared from acetone, ammonia gas and a 
catalyst under various conditions. The results are summarized in Table IV. 
Table IV 
__________________________________________________________________________ 
2.2.4.4.6 Pentamethyl-2,3,4,5 tetrahydropyrimidine from acetone and 
ammonia 
Catalyst 
as pre- Reaction 
Reaction 
Maximum 
Percent 
Ex. 
Acetone 
Ammonia 
pared in 
Catalyst 
time Tempera- 
pressure 
yield 
No. 
grams 
grams 
example 28 
grams 
hours 
ture .degree. C. 
psi of theory 
__________________________________________________________________________ 
29 174 50 none none 21 25-29 
58 5 
30 174 37 25 0.77 21 26-34 
48 55 
31 174 50 25 1.54 70 25-35 
44 65 
32 174 38 25 2.32 21 25-35 
42 66 
33 174 37 25 3.12 21 28-36 
43 69 
34 174 38 27 0.77 67 25-33 
48 66 
__________________________________________________________________________ 
EXAMPLE 34A 
2,4-Di-n-propyl-5-ethyl-2,3,4,5-tetrahydropyrimidine 
In a pressure reactor was placed 72 grams of butyraldehyde and 6 grams of 
ammonium chloride. To the mixture was added over a half hour period 23 
grams of ammonia gas. After the addition was completed the mixture was 
stirred for 23 more hours at ambient temperature. Ether was added to 
facilitate separation of the aqueous phase. The ethereal solution was 
evaporated under diminished pressure to yield 64.9 grams (99% of theory) 
of 2.4-di-n-propyl-5-ethyl-2,3,4,5-tetrahydropyrimidine; infrared spectrum 
3.08 m .mu. (weak) and 6.08 m .mu. strong absorption. 
Anal. Calc.ed for C.sub.12 H.sub.24 N.sub.2 : N, 14.28. Found: N, 14.05. 
EXAMPLE 35 
2-Phenyl-4.4.6-trimethyl-3,4,5,6-tetrahydropyrimidine 
A sample of 180 grams of 
2-phenyl-4.4.6-trimethyl-2,3,4,5-tetrahydropyrimidine was distilled under 
diminished pressure over 10 grams of potassium hydroxide. The fraction 69 
grams of b.sub.0.8 = 123.degree.-150.degree. C., which solidified during 
the distillation, as collected. Crystallization yielded 
2-phenyl-4.4.6-trimethyl-3,4,5,6-tetrahydropyrimidine as a white solid, 
m.p. 86.degree.-87.degree. C.; infrared spectrum 3.06 m .mu. weak (N--H) 
and 6.20 m .mu. strong (C.dbd.N), nuclear magnetic resonance spectrum, 
.tau. in ppm, solvent CHCl.sub.3, 2.28 multiplet 2H; 2.65 multiplet 3H; 
4.93 singlet 1H; 6.61 multiplet 1H; 8.42 multiplet 2H; 8.81 doublet 3H; 
8.82 singlet 3H; and 8.92 singlet 3H. 
Anal. Calc.ed for C.sub.13 H.sub.18 N.sub.2 : N, 13.86. Found: N, 13.6. 
EXAMPLE 36 
Glyoxal, mesityloxide, ammonia condensate 
A sample of 98 grams of mesityloxide and 200 cc. of 28% ammonium hydroxide 
was stirred for 3 hours. To the mixture was added 72.5 grams of a 40% aq. 
glyoxal solution. The mixture was stirred for 1/2 hour at ambient 
temperature and evaporated under diminished pressure. There was isolated 
65 grams of a red viscous liquid. 
Anal. Calc.ed for (C.sub.7 H.sub.13 N.sub.2).sub.x : N, 22.3. Found: N, 
21.9. 
EXAMPLE 37 
2.4.6-Collidine 
A sample of 54.8 grams of 2.4.4.6-tetramethyl-2,3,4,5-tetrahydropyrimidine 
was heated for 23 hours at reflux temperature, 168.degree.-179.degree. C. 
to yield 41.3 g. of a red liquid. 
Anal. Calc.ed for C.sub.8 H.sub.11 N: N, 11.58. Found: N, 11.38. 
Distillation of the product yielded 2.4.6 collidine, b.sub.20 = 
66.degree.-68.degree. C. identical spectral characteristic with authentic 
2.4.6 collidine. 
In a fashion as described in example 37, the following 6-substituted 
2.4-dimethylpyridines, collected in Table V were prepared from substituted 
4.4.6 trimethyl-2,3,4,5-tetrahydropyrimidines. 
Table V 
______________________________________ 
Starting Re- Reaction Nitro- 
mtl. prod- 
action Tempera- 
6-Substi- 
gen 
Ex. uct from time ture tuent in 
Calc. Anal. 
No. Exam. No. hours .degree. C. 
Product 
ed Found 
______________________________________ 
38 3 17 172-180 
n-propyl 
10.37 10.3 
39 4 21 180 n-hexyl 
7.92 7.8 
40 5 18 180 isopentyl 
8.58 8.3 
______________________________________ 
EXAMPLE 41 
2-n-Propyl-3.5-diethyl pyridine 
Into a mixture of 62.9 grams of 
2.4-di-n-propyl-5-ethyl-2,3,4,5-tetrahydropyrimidine, 4 grams of ammonium 
acetate and 4 grams of copper (II) acetate was introduced oxygen gas. 
Under continuous stirring and introduction of oxygen gas, the mixture was 
heated for 3 hours at 96.degree.-128.degree. C. The resulting reaction 
mixture was distilled under diminished pressure. The fraction b.sub.20 
122.degree.-126.degree. was collected as 37.2 grams (67.8% of theory) of 
2-n-propyl-3.5-diethyl pyridine; nuclear magnetic resonance spectrum, no 
solvent, .tau. in ppm 1.62 doublet 1H; 2.62 doublet 1H; 7.33 multiplet 6H; 
8.20 multiplet 2H; 8.82 triplet and 9.03 triplet 9H. 
Anal. Calc.ed for C.sub.12 H.sub.19 N: N, 7.91. Found: N, 7.8. 
The products of the above reactions where THP's are prepared are summarized 
in the following table 
TABLE A 
__________________________________________________________________________ 
##STR11## 
Ring 
Position 
6 5 4 4 2 2 
__________________________________________________________________________ 
Subst. 
Ex Group 
R.sub.1 
R.sub.2 
R.sub.3 
R.sub.4 
R.sub.5 
R.sub.6 
__________________________________________________________________________ 
1 CH.sub.3 
H CH.sub.3 
CH.sub.3 
CH.sub.3 
CH.sub.3 
2 CH.sub.3 
H CH.sub.3 
CH.sub.3 
H CH.sub.3 
3 CH.sub.3 
H CH.sub.3 
CH.sub.3 
H n-C.sub.3 H.sub.7 
4 CH.sub.3 
H CH.sub.3 
CH.sub.3 
H n-C.sub.6 H.sub.13 
5 CH.sub.3 
H CH.sub.3 
CH.sub.3 
H i-C.sub.5 H.sub.11 
6 CH.sub.3 
H CH.sub.3 
CH.sub. 3 
H Phenyl 
7 CH.sub.3 
H CH.sub.3 
CH.sub.3 
H i-C.sub.7 H.sub.15 
8 CH.sub.3 
H CH.sub.3 
CH.sub.3 
H n-C.sub.8 H.sub.17 
9 CH.sub.3 
H CH.sub.3 
CH.sub.3 
H CH.sub.3 
10 CH.sub.3 
H CH.sub.3 
CH.sub.3 
CH.sub.3 
CH.sub.3 
11 CH.sub.3 
H CH.sub.3 
CH.sub.3 
CH.sub.3 
C.sub.2 H.sub.5 
12 CH.sub.3 
H CH.sub.3 
CH.sub.3 
(CH.sub.2).sub.5 
13 CH.sub.3 
H CH.sub.3 
CH.sub.3 
##STR12## 
14 CH.sub.3 
H CH.sub.3 
CH.sub.3 
(CH.sub.2).sub.5 
15 
15- (CH.sub.2).sub.4 
(CH.sub.2).sub.5 
(CH.sub.2).sub.5 
23 
24 
##STR13## 
##STR14## 
##STR15## 
26 (CH.sub.2).sub.4 
(CH.sub.2).sub.5 
(CH.sub.2).sub.5 
28- 
34 CH.sub.3 
H CH.sub.3 
CH.sub.3 
CH.sub.3 
CH.sub.3 
34A H C.sub.2 H.sub.5 
H n-C.sub.3 H.sub.7 
H n-C.sub.3 H.sub.7 
__________________________________________________________________________ 
The compositions of this invention are useful as corrosion inhibitors, 
insecticides, anti-oxidants, biocides including bacterocides, fungicides, 
etc. 
The xanthates, besides being useful as a catalyst for the preparation of 
the tetrahydro pyrimidines of this invention, are also useful as corrosion 
inhibitors, oxygen scavengers, biocides, insecticides, etc. 
The compositions of this invention can be converted to a wide variety of 
derivatives including salts, quaternaries, isomerized pyrimidines, 
pyridines, etc.