29490-19-5

Basic information

• Product Name: 2-Mercapto-5-methyl-1,3,4-thiadiazole
• Synonyms: 2,3-Dihydro-5-methyl-1,3,4-thiadiazole-2-thione;2-Methyl-1,3,4-thiadiazole-5(4H)-thione;MMTD 2-Methyl-5-mercapto-1,3,4-thiadiazole;2-Mercapto-5-Methyl-1;MMTD)2-Mercapto-5-Methyl-1;Cefazolin IMpurity E;2-Mercapto-5-methyl-1,3,4-thiadiazole, 5-Methyl-1,3,4-thiadiazole-2-thiol;2-Methyl-5-thio-1,3,4-thiadiazole
• CAS NO: 29490-19-5
• Molecular Formula: C₃H₄N₂S₂
• Molecular Weight: 132.21
• EINECS: 249-667-1
• Product Categories: chemical additive;pharmaceutical intermediate;THIOL;API intermediates;Cephalosporins
• Mol File: 29490-19-5.mol
• Article Data: 17

Chemical Properties

• Melting Point: 185-188 °C
• Boiling Point: 182.9 °C at 760 mmHg
• Flash Point: 64.4 °C
• Appearance: /solid
• Density: 1.373 (estimate)
• Vapor Pressure: 0.791mmHg at 25°C
• Refractive Index: 1.5500 (estimate)
• Storage Temp.: Room temperature.
• Solubility: chloroform: soluble10mg/mL, clear to very slightly hazy, colorle
• PKA: 6.49±0.40(Predicted)
• Water Solubility: 2 g/100 mL
• BRN: 606663
• CAS DataBase Reference: 2-Mercapto-5-methyl-1,3,4-thiadiazole(CAS DataBase Reference)
• NIST Chemistry Reference: 2-Mercapto-5-methyl-1,3,4-thiadiazole(29490-19-5)
• EPA Substance Registry System: 2-Mercapto-5-methyl-1,3,4-thiadiazole(29490-19-5)

Safety Data

• Hazard Codes: Xi
• Statements: 36/37/38
• Safety Statements: 37/39-26
• WGK Germany: 3
• Hazardous Substances Data: 29490-19-5(Hazardous Substances Data)

Usage

Chemical Properties

white crystal powder

Uses

Different sources of media describe the Uses of 29490-19-5 differently. You can refer to the following data:
1. thiadiazole pharmaceutical intermediate
2. 5-Methyl-1,3,4-thiadiazol-2-thiol (Cefazolin EP Impurity E), is a new potent nitrification inhibitors. It is also an intermediate in the synthesis of Thiazolylacetylglycine Oxime (T344230).

General Description

5-Methyl-1,3,4-thiadiazole-2-thiol is a pharmaceutical intermediate. UV and UV/H2O2 induced degradation of 5-methyl-1,3,4-thiadiazole-2-thiol has been investigated.

InChI:InChI=1/C3H4N2S2/c1-2-4-5-3(6)7-2/h1H3,(H,5,6)

Synthetic route

C3H4N2S2*H3N → 2-mercapto-5-methyl-1,3,4-thiadiazole (29490-19-5)

Conditions	Yield
With hydrogenchloride In water at 30 - 35℃; for 0.5h; pH=4 - 4.5;	99.9%

Bis(2-methyl-1,3,4-thiadiazolyl)-5,5'-disulfide (66666-63-5) → 2-mercapto-5-methyl-1,3,4-thiadiazole (29490-19-5)

Conditions	Yield
With hydrazine In dichloromethane for 0.25h; Ambient temperature; further reagents;	87%

potassium N-acetylhydrazinodithioformate (38509-92-1) → 2-mercapto-5-methyl-1,3,4-thiadiazole (29490-19-5)

Conditions	Yield
With SO42-/TiO2-SnO2-Al2O3 solid super acid catalyst In tetrahydrofuran at -5 - 0℃; for 3.5h;	84.2%
With sulfuric acid at 5℃;
With sulfuric acid

ammonium N-acetylhydrazinodithioformate → 2-mercapto-5-methyl-1,3,4-thiadiazole (29490-19-5)

Conditions	Yield
With SO42-/TiO2-SnO2-Al2O3 solid super acid catalyst In tetrahydrofuran at -5 - 0℃; for 3.5h; Reagent/catalyst;	83.5%

delta-3 methyl ester of cefazolin (79239-19-3) → 2-mercapto-5-methyl-1,3,4-thiadiazole (29490-19-5)

Conditions	Yield
With phosphate buffer at 40℃; for 0.0833333h; Rate constant;

delta-3 methyl ester of cefazolin (79239-19-3) → cefazolin (25953-19-9) + 2-mercapto-5-methyl-1,3,4-thiadiazole (29490-19-5) + (6R,7R)-3-(5-Methyl-[1,3,4]thiadiazol-2-ylsulfanylmethyl)-8-oxo-7-(2-tetrazol-1-yl-acetylamino)-5-thia-1-aza-bicyclo[4.2.0]oct-3-ene-2-carboxylic acid + (6R,7R)-3-(5-Methyl-[1,3,4]thiadiazol-2-ylsulfanylmethyl)-8-oxo-7-(2-tetrazol-1-yl-acetylamino)-5-thia-1-aza-bicyclo[4.2.0]oct-3-ene-2-carboxylic acid methyl ester (117929-10-9)

Conditions	Yield
With phosphate buffer at 40℃; for 0.0833333h; Mechanism;

carbon disulfide (75-15-0) + thioacetamide (62-55-5) → 2-mercapto-5-methyl-1,3,4-thiadiazole (29490-19-5)

Conditions	Yield
With hydrazine 1) DMF, 0-5 deg C; 2) DMF, 0-5 deg C; 3) DMF, microwave irradiation, 1 min; Yield given. Multistep reaction;

5-methyl-1,3,4-thiadiazol-2-amine (108-33-8) → 2-mercapto-5-methyl-1,3,4-thiadiazole (29490-19-5)

Conditions	Yield
With potassium hydroxide; hydrogen bromide; copper; thiourea; sodium nitrite In ethanol

2-methyl-1,3,4-thiadiazoline-5-thione (29490-19-5) → 2-mercapto-5-methyl-1,3,4-thiadiazole (29490-19-5)

Conditions	Yield
In argon matrix at -263.16℃; for 2.25h; UV-irradiation;

carbon disulfide (75-15-0) + acetic anhydride (108-24-7) + thiosemicarbazide (79-19-6) → 2-mercapto-5-methyl-1,3,4-thiadiazole (29490-19-5)

Conditions	Yield
Stage #1: carbon disulfide; thiosemicarbazide With sodium carbonate In ethanol at 20 - 30℃; for 4.5h; Stage #2: acetic anhydride With sulfuric acid In ethanol at 0 - 20℃; for 2h; Reflux;

cefazolin sodium (27164-46-1) → C11H11N6O5S(1-)*Na(1+) + 2-mercapto-5-methyl-1,3,4-thiadiazole (29490-19-5)

Conditions	Yield
With β-lactamase at 37℃; for 0.5h; pH=7.4; Time; Alkaline conditions;

tetra(n-butyl)ammonium hydroxide (2052-49-5) + 2-mercapto-5-methyl-1,3,4-thiadiazole (29490-19-5) → (5-methyl-[1,3,4]-thiadiazole-2-thiolate)tetrabutylammonium (952021-15-7)

Conditions	Yield
In methanol for 3h; Inert atmosphere; Reflux;	100%
In methanol for 3h; Reflux; Inert atmosphere;

2-(trimethylsilyl)phenyl trifluoromethanesulfonate (88284-48-4) + 2-mercapto-5-methyl-1,3,4-thiadiazole (29490-19-5) → 5-methyl-2-phenylmercapto-1,3,4-thiadiazole (1298111-54-2)

Conditions	Yield
With cesium fluoride In acetonitrile for 6h; Reagent/catalyst; Solvent; Sealed tube; Inert atmosphere; Reflux;	100%

2-mercapto-5-methyl-1,3,4-thiadiazole (29490-19-5) + 3-iodopropyltrimethoxysilane (14867-28-8) → 5-methyl-2-[3-(trimethoxysilyl)propylthio]-1,3,4-thiadiazole

Conditions	Yield
Stage #1: 2-mercapto-5-methyl-1,3,4-thiadiazole With sodium methylate In methanol at 10 - 20℃; for 0.5h; Stage #2: 3-iodopropyltrimethoxysilane In methanol at 20 - 40℃; for 4.5h;	99.9%

2-(3,5-dichloro-4-oxopyridine-1(4H)-yl)acetic acid (56187-37-2) + 2-mercapto-5-methyl-1,3,4-thiadiazole (29490-19-5) → C10H7Cl2N3O2S2

Conditions	Yield
Stage #1: 2-(3,5-dichloro-4-oxopyridine-1(4H)-yl)acetic acid; 2-mercapto-5-methyl-1,3,4-thiadiazole With triethylamine In dichloromethane; N,N-dimethyl-formamide at 20℃; for 1h; Stage #2: With triphenyl phosphite In dichloromethane at 20 - 25℃; for 2h;	99.7%

[(2R,3S)-3-[(R)-1-(tert-Butyl-dimethyl-silanyloxy)-ethyl]-2-(2-chloro-acetylsulfanyl)-4-oxo-azetidin-1-yl]-(triphenyl-λ5-phosphanylidene)-acetic acid allyl ester (102628-07-9) + 2-mercapto-5-methyl-1,3,4-thiadiazole (29490-19-5) → {(2R,3S)-3-[(R)-1-(tert-Butyl-dimethyl-silanyloxy)-ethyl]-2-[2-(5-methyl-[1,3,4]thiadiazol-2-ylsulfanyl)-acetylsulfanyl]-4-oxo-azetidin-1-yl}-(triphenyl-λ5-phosphanylidene)-acetic acid allyl ester (102646-20-8)

Conditions	Yield
With triethylamine In N,N-dimethyl-formamide; acetonitrile for 1h; Ambient temperature;	99%

2-(3-bromopropyl)isoindole-1,3-dione (5460-29-7) + 2-mercapto-5-methyl-1,3,4-thiadiazole (29490-19-5) → 2-(3-(5-methyl-1,3,4-thiadiazol-2-ylthio)propyl)-1H-isoindole-1,3(2H)-dione (511304-52-2)

Conditions	Yield
With potassium carbonate In N,N-dimethyl-formamide at 90℃; for 6h; Inert atmosphere;	99%

1-Chloro-4-iodobenzene (637-87-6) + 2-mercapto-5-methyl-1,3,4-thiadiazole (29490-19-5) → C9H7ClN2S2

Conditions	Yield
With copper(l) iodide; potassium carbonate In N,N-dimethyl-formamide at 120℃; for 14h; Reagent/catalyst; Inert atmosphere;	98%

2-(3,5-dichloro-4-oxopyridine-1(4H)-yl)acetic acid (56187-37-2) + 2-mercapto-5-methyl-1,3,4-thiadiazole (29490-19-5) → C10H9Cl2N3O2S2

Conditions	Yield
Stage #1: 2-(3,5-dichloro-4-oxopyridine-1(4H)-yl)acetic acid; 2-mercapto-5-methyl-1,3,4-thiadiazole With pyridine In acetone at 20℃; for 1h; Stage #2: With triethyl phosphite In acetone at 20 - 25℃; for 2h; Solvent; Reagent/catalyst;	97%

C25H26N2O5S + 2-mercapto-5-methyl-1,3,4-thiadiazole (29490-19-5) → 7-phenylacetylamino-3-(2-methyl-1,3,4-thiadiazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid p-methoxybenzyl ester (107447-96-1)

Conditions	Yield
In acetone at 50 - 55℃; for 3h; Time;	97%

benzyl bromide (100-39-0) + 2-methyl-5-trimethylsilylthio-1,3,4-thiadiazole (81589-00-6) + 2-mercapto-5-methyl-1,3,4-thiadiazole (29490-19-5) + saccharin (81-07-2) → 2-[(phenylmethyl) thio]-5-methyl-1,3,4-thiadiazole (42755-32-8)

Conditions	Yield
With 1,1,1,3,3,3-hexamethyl-disilazane In N,N,N,N,N,N-hexamethylphosphoric triamide; water; ethyl acetate; acetonitrile	96.4%

(3R,4R)-4-{(1S)-3-chloro-2-oxo-1-methylpropoxy}-3-benzamido-1-(1-diphenylmethoxycarbonyl-1-triphenylphosphoranylidenemethyl)azetidin-2-one (90244-30-7) + 2-mercapto-5-methyl-1,3,4-thiadiazole (29490-19-5) → {(2R,3R)-3-Benzoylamino-2-[(S)-1-methyl-3-(5-methyl-[1,3,4]thiadiazol-2-ylsulfanyl)-2-oxo-propoxy]-4-oxo-azetidin-1-yl}-(triphenyl-λ5-phosphanylidene)-acetic acid benzhydryl ester (130793-04-3)

Conditions	Yield
In N,N-dimethyl-formamide for 1h; Ambient temperature;	96%

2-mercapto-5-methyl-1,3,4-thiadiazole (29490-19-5) + 3-acetoxymethyl-7-aminoceph-3-em-4-carboxylic acid → 7-amino-3-(5'-methyl-1',3',4'-thiadiazol-2'-ylthiomethyl)cephalosporanic acid (30246-33-4)

Conditions	Yield
With boric acid; triethylamine In water	96%
In water; acetone
In water; acetone

2-mercapto-5-methyl-1,3,4-thiadiazole (29490-19-5) + 4-chloro-benzenesulfenyl chloride (933-01-7) → 2-((4-chlorophenyl)disulfanyl)-5-methyl-1,3,4-thiadiazole (1402734-87-5)

Conditions	Yield
In diethyl ether at 28℃; for 12h;	96%

1-(2-chloroethyl)-3-methylurea (74378-14-6) + 2-mercapto-5-methyl-1,3,4-thiadiazole (29490-19-5) → N-Methyl-N'-<2-(5-methyl-1,3,4-thiadiazol-2-yl)-thioethyl>urea (74378-13-5)

Conditions	Yield
With triethylamine In acetonitrile for 3h; Heating;	95%

(6S,7S)-7-Azido-3-methanesulfonyloxymethyl-8-oxo-4-oxa-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid 4-nitro-benzyl ester + 2-mercapto-5-methyl-1,3,4-thiadiazole (29490-19-5) → p-nitrobenzyl 7-β-azido-3-<2-thio(5-methyl)-1,3,4-thiadiazolyl>methyl-Δ3-O-2-isocephem-4-carboxylate

Conditions	Yield
With triethylamine In dichloromethane at 23℃; for 16h;	95%

2-mercapto-5-methyl-1,3,4-thiadiazole (29490-19-5) + 7-Aminocephalosporanic acid (957-68-6) → (6R,7R)-7-amino-3-(5-methyl-1,3,4-thiadiazol-2-ylthiomethyl)-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid (30246-33-4)

Conditions	Yield
With boron trifluoride dimethyl carbonate complex; acetic acid at 5 - 10℃; Temperature;	95%
With boron trifluoride dimethyl carbonate complex; carbonic acid dimethyl ester at 20 - 30℃; for 1h; Reagent/catalyst;	92.1%
With boron trifluoride In acetonitrile at 30℃; for 1.5h;	86%

2-mercapto-5-methyl-1,3,4-thiadiazole (29490-19-5) + Stearoyl chloride (112-76-5) → Octadecanethioic acid S-(5-methyl-[1,3,4]thiadiazol-2-yl) ester (135363-52-9) + 3-stearoyl-5-methyl-1,3,4-thiadiazole-2(3H)-thione (135363-34-7)

Conditions	Yield
With triethylamine In dichloromethane Yields of byproduct given;	A n/a B 95%

trimethylaluminum (75-24-1) + 2-mercapto-5-methyl-1,3,4-thiadiazole (29490-19-5) + (1H-tetrazol-1-yl)-2-acetic acid methyl ester (55633-19-7) → 1H-tetrazole-1-acetic acid 2-methyl-1,3,4-thiadiazol-5-ylthiol ester

Conditions	Yield
In hexane; dichloromethane; ethyl acetate; Petroleum ether	95%

2-fluorobenzenesulfenyl chloride + 2-mercapto-5-methyl-1,3,4-thiadiazole (29490-19-5) → 2-((2-fluorophenyl)disulfanyl)-5-methyl-1,3,4-thiadiazole (1402734-90-0)

Conditions	Yield
In diethyl ether at 28℃; for 12h;	95%

2-(4-bromobutyl)isoindoline-1,3-dione (5394-18-3) + 2-mercapto-5-methyl-1,3,4-thiadiazole (29490-19-5) → 2-(4-((5-methyl-1, 3, 4-thiadiazol-2-yl)thio) butyl) isoindoline-1, 3-dione

Conditions	Yield
With tetrabutylammomium bromide; potassium carbonate In N,N-dimethyl-formamide at 20℃; for 6h; Inert atmosphere;	95%

2-mercapto-5-methyl-1,3,4-thiadiazole (29490-19-5) + 7-Aminocephalosporanic acid (957-68-6) → C11H12N4O3S3*ClH

Conditions	Yield
With boron trifluoride diethyl etherate; acetic acid at 5 - 10℃; Temperature;	95%

2-mercapto-5-methyl-1,3,4-thiadiazole (29490-19-5) + (4R-cis)-6-(chloromethyl)-2,2-dimethyl-1,3-dioxane-4-acetic acid,1,1-dimethylethyl ester (154026-94-5) → C16H26N2O4S2

Conditions	Yield
With N-benzyl-N,N,N-triethylammonium chloride; sodium carbonate In 1-methyl-pyrrolidin-2-one at 115℃; for 20h; Solvent; Reagent/catalyst; Inert atmosphere;	95%
With sodium carbonate In 1,4-dioxane at 80℃; for 6h; Inert atmosphere;

(R)-N-(2-(4-(4-bromobutoxy)phenyl)-2-hydroxyethyl)-N-methylacetamide + 2-mercapto-5-methyl-1,3,4-thiadiazole (29490-19-5) → (R)-N-(2-hydroxy-2-(4-(4-((5-methyl-1,3,4-thiadiazol-2-yl)thio)butoxy)phenyl)ethyl)-N-methylacetamide

Conditions	Yield
With potassium carbonate In N,N-dimethyl-formamide at 45 - 50℃; for 5h;	94.6%

2-bromo-5-nitro-1,3-thiazole (3034-48-8) + 2-mercapto-5-methyl-1,3,4-thiadiazole (29490-19-5) → 2-Methyl-5-[(5-nitrothiazol-2-yl)mercapto]-1,3,4-thiadiazole (40045-40-7)

Conditions	Yield
With potassium hydroxide In ethanol at 20℃;	94%

iodobenzene (591-50-4) + 2-mercapto-5-methyl-1,3,4-thiadiazole (29490-19-5) → 5-methyl-2-phenylmercapto-1,3,4-thiadiazole (1298111-54-2)

Conditions	Yield
With copper(l) iodide; potassium carbonate In N,N-dimethyl-formamide at 120℃; for 12h; Reagent/catalyst; Temperature; Solvent; Inert atmosphere;	94%

1,4-bromoiodobenzene (589-87-7) + 2-mercapto-5-methyl-1,3,4-thiadiazole (29490-19-5) → C9H7BrN2S2

Conditions	Yield
With copper(l) iodide; potassium carbonate In N,N-dimethyl-formamide at 120℃; for 14h; Reagent/catalyst; Inert atmosphere;	94%

p-methoxybenzyl 7β-(2-phenylacetamido)-3-chloromethyl-3-cephem-4-carboxylate (104146-10-3) + 2-mercapto-5-methyl-1,3,4-thiadiazole (29490-19-5) → 7-phenylacetylamino-3-[[2-(5-methyl-1,3,4-thiadiazolyl)thio]methyl]cephalosporanic acid p-methoxybenzyl ester

Conditions	Yield
With triethylamine In dichloromethane at 0℃; for 10h;	94%

C15H12BrCl2N3O5S + 2-mercapto-5-methyl-1,3,4-thiadiazole (29490-19-5) → cefazedone (56187-47-4)

Conditions	Yield
With triethylamine In ethanol for 10h; Solvent; Reagent/catalyst; Reflux;	93.86%

2-6-dimethoxybenzoic acid (1466-76-8) + 2-mercapto-5-methyl-1,3,4-thiadiazole (29490-19-5) → 2,6-dimethoxybenzoyl-(5-methyl-1,3,4-thiadiazol-2-il)thiol ester (86396-33-0)

Conditions	Yield
With pyridine; trichlorophosphate In dichloromethane for 16h; Ambient temperature;	93%

Upstream product

• 79239-19-3 delta-3 methyl ester of cefazolin 
• 38509-92-1 potassium N-acetylhydrazinodithioformate 
• 27164-46-1 cefazolin sodium 
• 75-15-0 carbon disulfide 
• 108-24-7 acetic anhydride 
• 79-19-6 thiosemicarbazide 
• 108-33-8 5-methyl-1,3,4-thiadiazol-2-amine 
• 62-55-5 thioacetamide 
• 66666-63-5 Bis(2-methyl-1,3,4-thiadiazolyl)-5,5'-disulfide 

Downstream Products

• 127867-51-0 Thiocarbonic acid O-benzyl ester S-(5-methyl-[1,3,4]thiadiazol-2-yl) ester 
• 127867-48-5 5-Methyl-2-thioxo-[1,3,4]thiadiazole-3-carboxylic acid benzyl ester 
• 485812-17-7 [CuBr(1,3-propanebis(diphenylphosphine))(5-methyl-1,3,4-thiazole-2-thione)] 
• 485812-16-6 [CuCl(1,3-propanebis(diphenylphosphine))(5-methyl-1,3,4-thiazole-2-thione)] 
• 180194-93-8 [(CH₃C₂N₂SS)HgC₆H₅] 
• 1169880-66-3 3-methoxy-5-(5-methyl-1,3,4-thiadiazol-2-ylthio)benzene-1,2-diol 
• 1169880-67-4 3-methoxy-4,5-bis(5-methyl-1,3,4-thiadiazol-2-ylthio)benzene-1,2-diol 
• 1169880-59-4 5-tert-butyl-4-(5-methyl-1,3,4-thiadiazol-2-ylthio)benzene-1,2-diol 
• 1169880-63-0 4-(5-methyl-1,3,4-thiadiazol-2-ylthio)benzene-1,2-diol 
• 1169880-65-2 4,5-bis(5-methyl-1,3,4-thiadiazol-2-ylthio)benzene-1,2-diol 
• 1169880-61-8 5-methyl-4-(5-methyl-1,3,4-thiadiazol-2-ylthio)benzene-1,2-diol 
• 1169880-68-5 3-methyl-4-(5-methyl-1,3,4-thiadiazol-2-ylthio)benzene-1,2-diol 
• 1169880-69-6 3-methyl-4,5-bis(5-methyl-1,3,4-thiadiazol-2-ylthio)benzene-1,2-diol 
• 75-15-0 carbon disulfide 

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