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Preparation of fungicidal compounds & use of fungicidal compounds and compositions comprising them on GM crops Disclosure Number: IPCOM000249876D
Publication Date: 2017-Apr-21

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Preparation of fungicidal compounds & use of fungicidal compounds and compositions comprising them on GM crops

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PART A: Preparation of fungicidal pyridylamidines  

The preparation of certain fungicidal pyridylamidines, including the preparation of N'‐[5‐bromo‐2‐methyl‐6‐(1‐methyl‐2‐

propoxy‐ethoxy)‐3‐pyridyl]‐N‐ethyl‐N‐methyl‐formamidine, is described in WO15155075 (see pages 26‐34) and WO17063973 

(see pages 57‐65). 


1‐propoxypropan‐2‐ol is an important intermediate in the preparation of N'‐[5‐bromo‐2‐methyl‐6‐(1‐methyl‐2‐propoxy‐ethoxy)‐

3‐pyridyl]‐N‐ethyl‐N‐methyl‐formamidine (compound 67.013, described in both WO15155075 and WO17063973). 



The intermediate “1‐propoxypropan‐2‐ol” can be synthesized from 2‐methyloxirane via ring opening of the epoxide with 

propan‐1‐ol.  1‐propoxypropan‐2‐ol is also commercially available from a variety sources, including: Aldrich, Dow and Nippon 

Nyukazai.  However, whether synthesised or obtained commercially, 1‐propoxypropan‐2‐ol is normally found to contain a small 

amount of its regioisomer, 2‐propoxypropan‐1‐ol, which results from attack of the nucleophile at the more sterically hindered 

carbon atom, Scheme 1 (below): 

2-propoxypropan-1-ol1-propoxypropan-2-ol A = major


B = minor   Scheme 1 


The resulting ratio of 1‐propoxypropan‐2‐ol to its regioisomer, 2‐propoxypropan‐1‐ol, is normally in the range of 90:10 to 

99.9:0.1 % w/w (ratio A:B, Scheme 1).   


A table of ratios typically observed when 1‐propoxypropan‐2‐ol is synthesised is given below in Table 1 (in % w/w): 

1‐propoxypropan‐2‐ol (A) 2‐propoxypropan‐1‐ol (B)

99.8% 0.2%

99.5% 0.5%

99%  1%

98%  2%

97%  3%

96%  4%

95%  5%

94%  6%

93%  7%

92%  8%

91%  9%

Table 1 


A table of ratios of A:B observed in commercially available 1‐propoxypropan‐2‐ol is given below in Table 2 (in % w/w): 

Commercial source  1‐propoxypropan‐2‐ol (A) 2‐propoxypropan‐1‐ol (B)

Aldrich  94.9% 4.76% 

Dow   95.0% 4.67% 

Nippon Nyukazai   96.5%   2.45% 

Table 2 


N'‐[5‐bromo‐2‐methyl‐6‐(1‐methyl‐2‐propoxy‐ethoxy)‐3‐pyridyl]‐N‐ethyl‐N‐methyl‐formamidine (compound 67.013, described 

in both WO15155075 and WO17063973). 

When a mixture of regioisomers as described in Scheme 1 or Table 1 above (1‐propoxypropan‐2‐ol and 2‐propoxypropan‐1‐ol) is 

used without separation and/or without further purification in the synthesis of N'‐[5‐bromo‐2‐methyl‐6‐(1‐methyl‐2‐propoxy‐

ethoxy)‐3‐pyridyl]‐N‐ethyl‐N‐methyl‐formamidine (compound 67.013, described in both WO15155075 and WO17063973) a 

mixture of regioisomeric products results (i.e. N'‐[5‐bromo‐2‐methyl‐6‐(1‐methyl‐2‐propoxy‐ethoxy)‐3‐pyridyl]‐N‐ethyl‐N‐

methyl‐formamidine and N'‐[5‐bromo‐2‐methyl‐6‐(2‐propoxypropoxy)‐3‐pyridyl]‐N‐ethyl‐N‐methyl‐formamidine), Scheme 2 


N'-[5-bromo-2-methyl-6-(1-methyl-2-propoxy- ethoxy)-3-pyridyl]-N-ethyl-N-methyl-formamidine

N'-[5-bromo-2-methyl-6-(2-propoxypropoxy)-3- pyridyl]-N-ethyl-N-methyl-formamidine

"Mitsonobu" conditions /



[N'-(5-bromo-6-hydroxy-2-methyl-3-pyridyl)-N-ethyl-N- methyl-formamidine: prepared according to procedures described in WO15155075 o...