Amidines

Amidines are a class of oxoacid derivatives and used as Building Blocks in Synthesis

  Synthesis of Amidines.

1. Amidines from nitriles

3-Cyanopyridine (52 g, 0.5 mol) was dissolved in MeOH (500 mL). Powdered NaOMe (2.7 g, 50 mmol) was added in one portion. The solution was stirred overnight at room temperature. After adding NH4Cl (30 g, 0.56 mol), the mixture was heated at reflux for 4 h and then cooled. The solvent was removed in vacuo. Absolute EtOH (600 mL) was added and the mixture was heated to reflux. After 15 min, the solids were filtered off and the mixture was allowed to cool to room temperature and stand overnight. Additional inorganic salts were filtered off, and the reaction mixture was concentrated to approximately 1/2 volume and filtered to afford 7.0 g of product (mp 186-188 oC). Concentration of the filtrate again to 1/2 its volume afforded an additional 25.0 g of product (mp 184-188 oC), followed by a third crop of 12.6 g (mp 184-188 oC) for a total of 44.6 g (57%) of 3-pyridinecarboximidamide.

2.Amidines from amides.

A solution of 0.1 mol of triethyloxonium fluoroborate in 50 ml of dry CHlCl2 was added to a suspension of 0.1 mol of the amide in 200 ml of dry CH2C12. The mixture was stirred overnight at room temperature. The solution was evaporated in Vacuo to one-third volume and treated with five volumes of anhydrous ether. The precipitated imidate fluoroborate was filtered and dried in uacuo. The salts could be recrystallized for analysis from dichloromethane or dichloromethane-ether. The crude salts were used in all cases for the amidine preparation. The imidate fluoroborate was stirred at room temperature in a tightly stoppered flrtsk with an 8-9% solution of ammonia or methylamine in absolute ethanol containing approximately a 40% excess of amine. After 3 days the mixture was evaporated to dryness in vacuo and treated with a small volume of water. The mixture was made strongly basic with 5 N NaOH and the insoluble oil was extracted into ethyl acetate or ether. The oil which remained after evaporation in vacuo of the organic solvent was either crystallized nnd purified or converted into the hydrochloride. A portion was also converted into the picrate.

3. Amidines from carboxylic acids

The following example is representative: PPSE was prepared from phosphorous pentoxide (1.42 g, 5 mmol) and hexamethyldisiloxane (2.56 g, 16 mmol) in 3 ml of CH2C12 at the refluxing temperature for 30 min, and the solvent was distilled away from the reaction mixture. To the residual syrup, p-methoxybenzoic acid (190 mg, 1.25 mmol) was added, and heated at 160 oC. After aniline (233 mg, 2.5 mmol) was added to the mixture, the solution was stirred at 160 oC for 5 h. The crude product was isolated by pouring the reaction mixture into 200 ml of cold 1M NaOH solution.

Recrystallization from aqueous ethanol gave pure N,N'-diphenylp-methoxybenzamidine melting at 115-116 oC (328 mg, 87%).

The application of Amidines.

1. Synthesis of six-membered rings, such as Pyridines, Pyrimidines, Triazines and Tetrazines.

 

2.Synthesis of five-membered rings, such as Imidazole derivatives.

 

3. Synthesis of three-membered rings.

 we deliver an innovative chemical database for your commercial sourcing

placing enquiry and order

over 25 kilo chemicals are available here for commercial sourcing.

enquiry can be placed on-line at http://www.ispharm.com/ or http://www.is-pharm.com/, by mailing to sales@ispharm.com or info@ispharm.com, and fax to +86 21 52685809.

we receive the order sent via the email and fax and the payment by paypal, credit card and t/t.

useful search functions online

search for the product by structure at http://www.ispharm.com/structure/search.html

search the cofa of the product online at homepage of http://www.ispharm.com/

search msds on the right side of the general information of every product

check the updated status of your order at http://www.ispharm.com/order/order_status.html

download our product list at http://www.ispharm.com/download/download.html

quality control

the standardization laboratory of is chemical technology in jinshan district, shanghai city, will provide the quality assurance for you. before delivery, all products pass through the structure identification and assay checking, and are attached with coa, nmr report and msds.

shipping and handling

is chemical technology commits to make every effort to ensure the delivery on schedule.

we use air express, such as fedex, dhl and ems, for most packages, and rate varies depend on location, package weight, and shipping type etc.

international shipping charge,

$45-55/per package (quantity: <0.5kg);

poa for quantities over 0.5 kg

credit

is chemical technology pays more attention to the business credit and has been devoting to establish sincere and faithful business relation with the partners. in 2009, is chemical technology took the lead in cooperating with dun & bradstreet, the world leading credit management and consulting agency, participating in the d&b d-u-n-s registered program of the company.