CA2446918A1 - Process for producing thiosemicarbazides - Google Patents
Process for producing thiosemicarbazides Download PDFInfo
- Publication number
- CA2446918A1 CA2446918A1 CA002446918A CA2446918A CA2446918A1 CA 2446918 A1 CA2446918 A1 CA 2446918A1 CA 002446918 A CA002446918 A CA 002446918A CA 2446918 A CA2446918 A CA 2446918A CA 2446918 A1 CA2446918 A1 CA 2446918A1
- Authority
- CA
- Canada
- Prior art keywords
- thiosemicarbazide
- producing
- mtsc
- dipea
- alkyl
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D285/00—Heterocyclic compounds containing rings having nitrogen and sulfur atoms as the only ring hetero atoms, not provided for by groups C07D275/00 - C07D283/00
- C07D285/01—Five-membered rings
- C07D285/02—Thiadiazoles; Hydrogenated thiadiazoles
- C07D285/04—Thiadiazoles; Hydrogenated thiadiazoles not condensed with other rings
- C07D285/12—1,3,4-Thiadiazoles; Hydrogenated 1,3,4-thiadiazoles
- C07D285/125—1,3,4-Thiadiazoles; Hydrogenated 1,3,4-thiadiazoles with oxygen, sulfur or nitrogen atoms, directly attached to ring carbon atoms, the nitrogen atoms not forming part of a nitro radical
- C07D285/135—Nitrogen atoms
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C337/00—Derivatives of thiocarbonic acids containing functional groups covered by groups C07C333/00 or C07C335/00 in which at least one nitrogen atom of these functional groups is further bound to another nitrogen atom not being part of a nitro or nitroso group
- C07C337/06—Compounds containing any of the groups, e.g. thiosemicarbazides
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Nitrogen- Or Sulfur-Containing Heterocyclic Ring Compounds With Rings Of Six Or More Members (AREA)
Abstract
A process is provided for producing a thiosemicarbazide which includes the steps of reacting an alkylamine with carbon disulphide in the presence of a base selected from N,N-diisopropylethylamine and N,N,-diisopropyl-methylamin e to produce an intermediate and converting the intermediate into the thiosemicarbazide. The process has particular application to producing 4- methyl-3-thiosemicarbazide, an intermediate useful in producing the broad- spectrum herbicide tebuthiuron.
Description
r 05-05-2003 CA 02446918 2003-10-O1 IB020102~
. . 14:52 F.9~ 011 884 4660 SPOOR & FISHER C~,.,., ., r - l1 -' BACt~GROUND OF ThiE INVENTION
This invention relates to a process for producing ithiosemicarbazides.
4-Methyl-3-thiosemicarbazide (MTSC) is an inten~ediate in the synthesis of 5-t-butyl-Z-methylamino-1,3,4-thiadiazole ~(BTDA), the precursor of tebuthiuron, a broad-spectrum herbicide. Tebuthiuron has the chemical name 1-(5-tent butyl-1,3,4-thiadiazol-2-yl)-1,3 dimethylurea.
Several syntheses of thiosemicarbazides, substituted in the 4-position, are described in literature and may be broadly grouped asfollvuvs:
the reacfion of alkyl isothiocyanates with hydrazine, ~ the reaction of hydrazine with reactive: thivcarbamic acid derivatives (acid chlorides, thiuram monosutfides, etc.), and ~ the hydrazinolysis of N-monoalkyl- and N.N-dialkytdithio-carbamates.
The current production process for MTSG entails. the hydrazinvlysis of ammonium N-methyl-dithiocarbamate, Methyl isothiocyanate (MITC) is believed to be formed in situ from ammonium N-methyldithiocatbamate when heated in the presence of bases. It reacts with hydrazine monohydrate to give MTSC. This process affords MTSC of 93-94°!o purity. The purify of MTSG is a critical factor in the manufacturing of BTDA of high purity (98*°!°) and yield. The MTSC produced by this process is of , insuffcient~ quality to produce high quality BTDA. This process also generates efFluents containing high concentrations of ammonium salts. The large volume of , effluent produced during this process is a major problem (approximately four tuns of effluent are produced far every ton of MTSC produced on plant scale).
EP339964 discloses a process for producing MTSC by reacting methylamine with carbon disulphide in the presence of a base which is triethylamine. Although goad yields of MTSC are obtained (F~cample 1:$O,O~o, Example 3:81,4°!0, F~cample 4:86,1°!0), it would be a advantageous to use a method for producing MTSC which provides a higher purity product, a better recovery of tfie base, and less effluents.
Empf .~eit:05/fl AMENDED SHEET
. . 14:52 F.9~ 011 884 4660 SPOOR & FISHER C~,.,., ., r - l1 -' BACt~GROUND OF ThiE INVENTION
This invention relates to a process for producing ithiosemicarbazides.
4-Methyl-3-thiosemicarbazide (MTSC) is an inten~ediate in the synthesis of 5-t-butyl-Z-methylamino-1,3,4-thiadiazole ~(BTDA), the precursor of tebuthiuron, a broad-spectrum herbicide. Tebuthiuron has the chemical name 1-(5-tent butyl-1,3,4-thiadiazol-2-yl)-1,3 dimethylurea.
Several syntheses of thiosemicarbazides, substituted in the 4-position, are described in literature and may be broadly grouped asfollvuvs:
the reacfion of alkyl isothiocyanates with hydrazine, ~ the reaction of hydrazine with reactive: thivcarbamic acid derivatives (acid chlorides, thiuram monosutfides, etc.), and ~ the hydrazinolysis of N-monoalkyl- and N.N-dialkytdithio-carbamates.
The current production process for MTSG entails. the hydrazinvlysis of ammonium N-methyl-dithiocarbamate, Methyl isothiocyanate (MITC) is believed to be formed in situ from ammonium N-methyldithiocatbamate when heated in the presence of bases. It reacts with hydrazine monohydrate to give MTSC. This process affords MTSC of 93-94°!o purity. The purify of MTSG is a critical factor in the manufacturing of BTDA of high purity (98*°!°) and yield. The MTSC produced by this process is of , insuffcient~ quality to produce high quality BTDA. This process also generates efFluents containing high concentrations of ammonium salts. The large volume of , effluent produced during this process is a major problem (approximately four tuns of effluent are produced far every ton of MTSC produced on plant scale).
EP339964 discloses a process for producing MTSC by reacting methylamine with carbon disulphide in the presence of a base which is triethylamine. Although goad yields of MTSC are obtained (F~cample 1:$O,O~o, Example 3:81,4°!0, F~cample 4:86,1°!0), it would be a advantageous to use a method for producing MTSC which provides a higher purity product, a better recovery of tfie base, and less effluents.
Empf .~eit:05/fl AMENDED SHEET
SUMMARY OF THE INVENTION
According to a first aspect of the invention, a process for producing a thiosemicarbazide includes the steps of reacting an alkylamine with carbon disulphide in the presence of a base selected from N,N-diisopropylethylamine (DIPEA) and N,N,-diisopropylmethylamine (DIPMA) to produce an intermediate and converting the intermediate into the thiosemicarbazide. It is preferred that the reaction of the alkylamine with the carbon disulphide takes place in the presence of an excess of the base.
The intermediate is an N,N-diisopropyl-ethylammonium dithiocarbamate or a N,N-diisopropyl-methylammonium dithiocarbamate. Both intermediates are believed to be new and form another aspect of the invention. The structure of N,N-diisopropylethyl ammonium N-alkyl dithiocarbamate is:
/~\~ of alkyl NH S N H
The invention further provides a method of producing an N,N-diisopropyl-ethylammonium dithiocarbamate or an N,N-diisopropyl-methylammonium dithiocarbamate by reacting an alkylamine with carbon disulphide in the presence of DIPEA or DIPMA.
According to a first aspect of the invention, a process for producing a thiosemicarbazide includes the steps of reacting an alkylamine with carbon disulphide in the presence of a base selected from N,N-diisopropylethylamine (DIPEA) and N,N,-diisopropylmethylamine (DIPMA) to produce an intermediate and converting the intermediate into the thiosemicarbazide. It is preferred that the reaction of the alkylamine with the carbon disulphide takes place in the presence of an excess of the base.
The intermediate is an N,N-diisopropyl-ethylammonium dithiocarbamate or a N,N-diisopropyl-methylammonium dithiocarbamate. Both intermediates are believed to be new and form another aspect of the invention. The structure of N,N-diisopropylethyl ammonium N-alkyl dithiocarbamate is:
/~\~ of alkyl NH S N H
The invention further provides a method of producing an N,N-diisopropyl-ethylammonium dithiocarbamate or an N,N-diisopropyl-methylammonium dithiocarbamate by reacting an alkylamine with carbon disulphide in the presence of DIPEA or DIPMA.
DESCRIPTION OF EMBODIMENTS
The alkylamine which is used in the process of the invention has the formula alkyl-NH2, i.e. a primary alkylamine. The preferred alkyl is methyl.
The thiosemicarbazide which is produced by the process of the invention may have the formula:
R~NH-CS-NH-NHZ
wherein R, is alkyl.
The invention has particular application to producing MTSC and an intermediate therefor, N,N-diisopropyl-ethylammonium dithiocarbamate, following steps 1 and 2 set out hereinafter:
Step 1 \ p CHI NHZ + CSZ + N ~ CH, NH S N H
(A) Step 2 s a ~
/C\6 ~~ ~C\ _ + N + H,S
CHI NH S ~ N H + HZNNHZ.HiO --~ CHI NH HN NHz In the above process, it is preferred that an excess of DIPEA is used. This forces the reaction of step 1 to the right and increases the stability of the intermediate (A). Typically, an excess of 10% to 30% DIPEA is used.
The reaction of step 1 is highly exothermic and cooling is generally necessary to maintain the temperature of the reaction medium below 30°C.
Using DIPEA as a base in producing MTSC, reduces substantially the amount of effluent which is produced. Further, the intermediate (A) has been shown to have significant stability resulting in a decrease in the formation of by-products such as thiocarbohydrazide and dimethylthiourea. Further, MTSC in yields of 70 to 76% and purities of 97,5 to 98,5% are attainable.
Examples of the invention will now be described.
EXAMPLE 1 (10% excess of DIPEA) Methylamine (77,58; 40% solution) and DIPEA (142,2g) were charged to a 1 litre reactor equipped with a reflux condenser and a stirrer. CS2 (76g) was added dropwise with stirring during 30 minutes. The reaction temperature was maintained below 30°C by external cooling during the addition of CS2.
The mixture was stirred for an additional 3 hours after which distillate (60g) from a previous batch was added. The reaction mixture was diluted with water to obtain a DTC (dithiocarbamate) concentration of 24%.
Hydrazine hydrate (60,1 g) was added to the DIPEA-DTC mixture. The reaction mixture was heated to 89°C and maintained at 89 to 92°C
under reflux conditions for 2 hours and 20 minutes. The DIPEA was distilled off (distillation is complete when the temperature rises above 95°C), the reaction mixture cooled to 15°C while stirring, and the MTSC crystals separated from the supernatant layer, providing a 73,8% isolated yield of MTSC. The purity of MTSC was 98.0%.
EXAMPLE 2 (30% excess of DIPEA) Methylamine (38.7g; 40% solution) and DIPEA (82.4g) were charged to a 0,5 Titre reactor equipped with a reflux condenser and a stirrer. CSz (38.1g) was added dropwise with stirring during 30 minutes. The reaction temperature was maintained below 30°C by external cooling during the addition of CSz.
The mixture was stirred for an additional 3 hours after which distillate (30g) from a previous batch was added. The reaction mixture was diluted with water to obtain a DTC (dithiocarbamate) concentration of 24%.
Hydrazine hydrate (30,1 g) was added to the DIPEA-DTC mixture. The reaction mixture was heated to 92°C and maintained at 92°C under reflux conditions for 2 hours and 20 minutes. The DIPEA was distilled off (distillation is complete when the temperature rises above 95°C), the reaction mixture cooled to 15°C while stirring, and the MTSC crystals separated from the supernatant layer, providing a 75,8% isolated yield of MTSC.
J
The alkylamine which is used in the process of the invention has the formula alkyl-NH2, i.e. a primary alkylamine. The preferred alkyl is methyl.
The thiosemicarbazide which is produced by the process of the invention may have the formula:
R~NH-CS-NH-NHZ
wherein R, is alkyl.
The invention has particular application to producing MTSC and an intermediate therefor, N,N-diisopropyl-ethylammonium dithiocarbamate, following steps 1 and 2 set out hereinafter:
Step 1 \ p CHI NHZ + CSZ + N ~ CH, NH S N H
(A) Step 2 s a ~
/C\6 ~~ ~C\ _ + N + H,S
CHI NH S ~ N H + HZNNHZ.HiO --~ CHI NH HN NHz In the above process, it is preferred that an excess of DIPEA is used. This forces the reaction of step 1 to the right and increases the stability of the intermediate (A). Typically, an excess of 10% to 30% DIPEA is used.
The reaction of step 1 is highly exothermic and cooling is generally necessary to maintain the temperature of the reaction medium below 30°C.
Using DIPEA as a base in producing MTSC, reduces substantially the amount of effluent which is produced. Further, the intermediate (A) has been shown to have significant stability resulting in a decrease in the formation of by-products such as thiocarbohydrazide and dimethylthiourea. Further, MTSC in yields of 70 to 76% and purities of 97,5 to 98,5% are attainable.
Examples of the invention will now be described.
EXAMPLE 1 (10% excess of DIPEA) Methylamine (77,58; 40% solution) and DIPEA (142,2g) were charged to a 1 litre reactor equipped with a reflux condenser and a stirrer. CS2 (76g) was added dropwise with stirring during 30 minutes. The reaction temperature was maintained below 30°C by external cooling during the addition of CS2.
The mixture was stirred for an additional 3 hours after which distillate (60g) from a previous batch was added. The reaction mixture was diluted with water to obtain a DTC (dithiocarbamate) concentration of 24%.
Hydrazine hydrate (60,1 g) was added to the DIPEA-DTC mixture. The reaction mixture was heated to 89°C and maintained at 89 to 92°C
under reflux conditions for 2 hours and 20 minutes. The DIPEA was distilled off (distillation is complete when the temperature rises above 95°C), the reaction mixture cooled to 15°C while stirring, and the MTSC crystals separated from the supernatant layer, providing a 73,8% isolated yield of MTSC. The purity of MTSC was 98.0%.
EXAMPLE 2 (30% excess of DIPEA) Methylamine (38.7g; 40% solution) and DIPEA (82.4g) were charged to a 0,5 Titre reactor equipped with a reflux condenser and a stirrer. CSz (38.1g) was added dropwise with stirring during 30 minutes. The reaction temperature was maintained below 30°C by external cooling during the addition of CSz.
The mixture was stirred for an additional 3 hours after which distillate (30g) from a previous batch was added. The reaction mixture was diluted with water to obtain a DTC (dithiocarbamate) concentration of 24%.
Hydrazine hydrate (30,1 g) was added to the DIPEA-DTC mixture. The reaction mixture was heated to 92°C and maintained at 92°C under reflux conditions for 2 hours and 20 minutes. The DIPEA was distilled off (distillation is complete when the temperature rises above 95°C), the reaction mixture cooled to 15°C while stirring, and the MTSC crystals separated from the supernatant layer, providing a 75,8% isolated yield of MTSC.
J
Claims (7)
1. A process for producing a thiosemicarbazide includes the steps of reading an alkylamine with carbon disulphide in the presence of a base selected from N,N-diisopropylethylamine and N,N,-diisopropyl-methylamine to produce an intermediate and converting the intermediate into the thiosemicarbazide.
2. A process according to claim 1 wherein the thiosemicarbazide has the formula:
R1NH-CS-NH-NH2, wherein R1 is alkyl
R1NH-CS-NH-NH2, wherein R1 is alkyl
3. A process according to claim 1 wherein the thiosemicarbazide is 4-methyl-3-thiosemicarbazide.
4. A process according to any one of the preceding claims wherein the reaction of the alkylamine with carbon disulphide takes place in the presence of an excess of the base.
5. A compound selected from N,N-diisopropylethylammonium N-alkyl dithiocarbamate and N,N-diisopropylmethylammonium N-alkyl dithio-carbamate.
6. The use of a compound according to claim 6 in producing a thiosemicarbazide.
7. The use of a compound according to claim 5 in producing 1-(5-tert-butyl-1,3,4-thiadiazol-2-yl)-1,3 dimethylurea.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| ZA200102904 | 2001-04-09 | ||
| ZA2001/2904 | 2001-04-09 | ||
| PCT/IB2002/001023 WO2002081438A2 (en) | 2001-04-09 | 2002-04-02 | Process for producing thiosemicarbazides |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2446918A1 true CA2446918A1 (en) | 2002-10-17 |
Family
ID=25589131
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002446918A Abandoned CA2446918A1 (en) | 2001-04-09 | 2002-04-02 | Process for producing thiosemicarbazides |
Country Status (10)
| Country | Link |
|---|---|
| EP (1) | EP1377546A2 (en) |
| JP (1) | JP2004536795A (en) |
| KR (1) | KR20030086351A (en) |
| CN (1) | CN1518539A (en) |
| BR (1) | BR0208743A (en) |
| CA (1) | CA2446918A1 (en) |
| HU (1) | HUP0303844A2 (en) |
| IL (1) | IL158288A0 (en) |
| MX (1) | MXPA03009215A (en) |
| WO (1) | WO2002081438A2 (en) |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102584661A (en) * | 2012-01-19 | 2012-07-18 | 中国科学院海洋研究所 | Preparation method of substituted phenylthiosemicarbazide compound |
| CN103709081B (en) * | 2013-12-13 | 2016-01-06 | 黄河三角洲京博化工研究院有限公司 | A kind of preparation method of thiosemicarbazide |
| CN104860857B (en) * | 2015-04-09 | 2017-03-08 | 山东华阳农药化工集团有限公司 | Methylthiosemicarbazone synthesis technique |
| CN105797769B (en) * | 2016-04-06 | 2018-03-30 | 上海应用技术学院 | (R) the thiourea modified Mn Anderson types heteropolyacid catalyst of 1 (phenethyl of 2 hydroxyl 1), preparation method and applications |
| CN105772086B (en) * | 2016-04-06 | 2018-03-30 | 上海应用技术学院 | (S) the thiourea modified Mn Anderson types heteropolyacid catalyst of 1 (isopropyl of 1 ethoxy 1), preparation method and applications |
| CN105797770B (en) * | 2016-04-06 | 2018-03-30 | 上海应用技术学院 | (S) the thiourea modified Cr Anderson types heteropolyacid catalyst of 1 (phenylpropyl of 3 hydroxyl 1), preparation method and applications |
| CN105772101B (en) * | 2016-04-06 | 2018-03-30 | 上海应用技术学院 | The Mn Anderson types heteropolyacid catalyst of 1 Phenethylthiourea modification, preparation method and applications |
| CN105854952B (en) * | 2016-04-06 | 2018-05-15 | 上海应用技术学院 | (S) Mn-Anderson types heteropolyacid catalyst thiourea modified -1- (2- hydroxyl -1- phenethyls), preparation method and applications |
| CN105772100B (en) * | 2016-04-06 | 2018-05-15 | 上海应用技术学院 | (R) Cr-Anderson types heteropolyacid catalyst thiourea modified -1- (1- (2- naphthyls) ethyl), preparation method and applications |
| CN105854940B (en) * | 2016-04-06 | 2018-05-15 | 上海应用技术学院 | (R) Cr-Anderson types heteropolyacid catalyst thiourea modified -1- (1- phenethyls), preparation method and applications |
| CN105833909B (en) * | 2016-04-06 | 2018-05-15 | 上海应用技术学院 | (S) Cr-Anderson types heteropolyacid catalyst thiourea modified -1- (2- hydroxyl -1- phenethyls), preparation method and applications |
| CN105772085B (en) * | 2016-04-06 | 2018-04-13 | 上海应用技术学院 | (S) the thiourea modified Cr Anderson types heteropolyacid catalyst of 1 (1 ethoxy, 1 isopropyl), preparation method and applications |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA931961A (en) * | 1970-04-17 | 1973-08-14 | Gulf Research And Development Company | Combating unwanted vegetation with 1,3,4-thiadiazolylureas |
| JPH0211562A (en) * | 1988-04-27 | 1990-01-16 | Eli Lilly & Co | Production of 4-methyl-3-thiosemicarbazide |
-
2002
- 2002-04-02 CN CNA028078977A patent/CN1518539A/en active Pending
- 2002-04-02 HU HU0303844A patent/HUP0303844A2/en unknown
- 2002-04-02 KR KR10-2003-7013168A patent/KR20030086351A/en not_active Application Discontinuation
- 2002-04-02 MX MXPA03009215A patent/MXPA03009215A/en unknown
- 2002-04-02 CA CA002446918A patent/CA2446918A1/en not_active Abandoned
- 2002-04-02 BR BR0208743-0A patent/BR0208743A/en not_active Application Discontinuation
- 2002-04-02 EP EP02716977A patent/EP1377546A2/en not_active Withdrawn
- 2002-04-02 IL IL15828802A patent/IL158288A0/en unknown
- 2002-04-02 WO PCT/IB2002/001023 patent/WO2002081438A2/en not_active Application Discontinuation
- 2002-04-02 JP JP2002579426A patent/JP2004536795A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| IL158288A0 (en) | 2004-05-12 |
| KR20030086351A (en) | 2003-11-07 |
| JP2004536795A (en) | 2004-12-09 |
| CN1518539A (en) | 2004-08-04 |
| WO2002081438A3 (en) | 2002-11-28 |
| BR0208743A (en) | 2004-06-22 |
| WO2002081438A2 (en) | 2002-10-17 |
| HUP0303844A2 (en) | 2004-03-29 |
| MXPA03009215A (en) | 2004-03-10 |
| EP1377546A2 (en) | 2004-01-07 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |