BACKGROUND OF THE INVENTION

The most closely related ether to applicant's novel compounds of which applicant is aware are those disclosed in U.S. Pat. No. 3,119,682 which discloses 3-[p-(p-chlorophenoxy)phenyl]-1,1-dimethylurea. It would be readily apparent that the compound of the above cited U.S. patent is only remotely related to applicants' novel compounds due to the lack of the presence of the dioxane radical.

BRIEF DESCRIPTION OF THE INVENTION

This invention relates to novel benzodioxanes having the formula ##STR3## in which R is selected from the group consisting of alkoxy having from 1 to 6 carbon atoms, preferably having from 1 to 3 carbon atoms and more preferably --OCH.sub.3, cycloalkyl having from 3 to 6 carbon atoms, preferably cyclopropyl, alkyl having from 1 to 6 carbon atoms, preferably having from 2 to 4 carbon atoms and more preferably ethyl, thioalkyl having from 1 to 6 carbon atoms, preferably having from 1 to 3 carbon atoms and more preferably thiomethyl, chloroalkyl having from 1 to 6 carbon atoms, preferably having from 2 to 4 carbon atoms and more preferably chloroethyl, alkynyl having from 2 to 6 carbon atoms, preferably having from 2 to 4 carbon atoms and more preferably vinyl ##STR4## wherein R.sub.2 is alkyl having from 1 to 6 carbon atoms, preferably from 1 to 3 carbon atoms and more preferably methyl, or alkoxy having from 1 to 6 carbon atoms, preferably from 1 to 3 carbon atoms and more preferably methoxy and R.sub.3 is hydrogen or alkyl having from 1 to 6 carbon atoms, preferably from 1 to 3 carbon atoms and more preferably is methyl. The compounds are useful as herbicides when used in a herbicidally effective amount.

The term "herbicides" as used herein means a compound which control or modifies growth of plants. By the term "herbicidally effective amount" is meant an amount of compound which causes a modifying effect upon the growth of plants. By "plants" is meant germinant seeds, emerging seedlings and established vegetation, including roots and above-ground portions. Such modifying effects include all deviations from natural development; for example, killing, retardation, defoliation, desiccation, regulation, stunting, tillering, stimulation, leaf burn, dwarfing and the like.

The compounds of the present invention, as will be seen from the data which follows, have utility as post-emergence herbicides, against a wide range of plant species.

DETAILED DESCRIPTION OF THE INVENTION

Novel intermediate compounds having the formulas ##STR5## which are useful in preparing the novel herbicidal compounds of the present invention are prepared in the following general manner:

(1) 2-BENZPYRANYLMETHYL-2-CHLORO-4,4-NITROPHENYL ETHER

The condensation of 3,4-dichloronitrobenzene is conducted in a polar solvent (non-reacting solvent) such as dimethylsulfoxide or water with the sodium or potassium salt of the hydroxymethyl 1,4-benzodioxane. The salt can be prepared from the alcohol and NaH or potassium t-butoxide or under certain conditions with NaOH or KOH.

(2) 2-BENZPYRANYLMETHYL-2-CHLORO-4-AMINOPHENYL ETHER

The reduction of the nitro group of the above compound is effected by several means such as catalytically with H.sub.2 and a nobel metal catalyst or with iron in ethanol-water (50:50 by weight) using hydrochloric acid.

The novel compounds of the present invention which are defined by the formula ##STR6## in which R is selected from the group consisting of alkoxy having from 1 to 6 carbon atoms, preferably having from 1 to 3 carbon atoms and more preferably --OCH.sub.3, cycloalkyl having from 3 to 6 carbon atoms, preferably cyclopropyl, alkyl having from 1 to 6 carbon atoms, preferably having from 2 to 4 carbon atoms and more preferably ethyl, thioalkyl having from 1 to 6 carbon atoms, preferably having from 1 to 3 carbon atoms and more preferably thiomethyl, chloroalkyl having from 1 to 6 carbon atoms, preferably having from 2 to 4 carbon atoms and more preferably chloroethyl, alkynyl having from 2 to 6 carbon atoms, preferably having from 2 to 4 carbon atoms and more preferably vinyl ##STR7## wherein R.sub.2 is alkyl having from 1 to 6 carbon atoms, preferably from 1 to 3 carbon atoms and more preferably methyl, or alkoxy having from 1 to 6 carbon atoms, preferably from 1 to 3 carbon atoms and more preferably methoxy and R.sub.3 is hydrogen or alkyl having from 1 to 6 carbon atoms, preferably from 1 to 3 carbon atoms and more preferably is methyl exhibit herbicidal activity and are prepared (from the intermediate 2-benzpyranylmethyl-2-chloro-4-aminophenyl ether) by reacting an appropriately substituted acid chloride with the aniline type intermediate compound 2-benzpyranylmethyl-2-chloro-4-aminophenyl ether in an inert solvent such as acetone, ether, methylene chloride, chloroform, toluene or benzene. The reaction is preferably conducted at a temperature of from about -50.degree. C. to about 100.degree. C. Acid binding agents such as pyridine triethylamine, sodium hydroxide and dimethyl aniline may be employed.

Although the above reactions will proceed at any temperature, side reactions become more prominent at higher temperatures raising the level of impurities in the final product. For this reason, it is preferred to run the reaction at from about -40.degree. C. to about 0.degree. C., and most preferably at about -30.degree. C.

The examples shown herein are illustrative of the method of preparation of both intermediates and compounds of the invention.

Specific compound preparation and herbicidal activity of the compounds of this invention are shown in the following examples.

EXAMPLE I

2-Benzpyranylmethyl-2-Chloro-4-Nitrophenyl Ether

To a mixture of 25 grams (g.) (0.15 mole) 2-hydroxymethyl-1,4-benzodioxane in 200 milliliters (ml.) dimethyl sulfoxide was added 4.6 g. (0.196 mole) sodium hydride. Then 29 g. (0.15 mole) 3,4-dichloronitrobenzene was added. The reaction was exothermic to 60.degree. C. After the exotherm ceased, the mixture was heated to 70.degree. C. for 5 minutes and then cooled to 0.degree. C. Fifty g. of ice and 400 ml. methylene chloride were then added. The reaction mixture was then washed with ice water (200 ml.), 10 ml. 10% NaOH, 200 ml. 1 N hydrochloric acid and 100 ml. saturated sodium carbonate solution. The washed solution was dried over magnesium sulfate and evaporated in vacuo to give 44.1 g. of product having a melting point of 113.degree.-114.degree. C. The product was identified as the title product by infrared (IR) and nuclear magnetic resonance (NMR) spectra analyses.

EXAMPLE II

2-Benzpyranylmethyl-2-Chloro-4-Aminophenyl Ether

Under an argon atmosphere, 22.3 g. electrolyte iron, 64 ml. ethanol and 53.4 ml. water were mixed together. To the resultant stirred mixture was added in one portion 1.88 ml. concentrated hydrochloric acid and the resulting mixture heated to reflux. 4.1 g. of the nitro ether prepared in Example I was added to this hot stirred mixture. The addition was made in portions of near reflux temperatures. The mixture was then refluxed for 30 minutes and 1.26 ml. of 50% sodium hydroxide solution was added. This mixture was filtered while hot through dicalite. The filtrate was concentrated in vacuo and then taken up in 200 ml. of methylene chloride, washed with two 500 ml. portions of water and four 100 ml. portions of saturated sodium carbonate solution. The washed mixture was dried over magnesium sulfate and evaporated in vacuo to yield 34 g. of product having a m.p. of 90.degree.-91.degree. C. The product was identified as the title product by IR and NMR analyses.

EXAMPLE III

O-Methyl-4-(Benz-1,4-Dioxane-2-Methoxy)-3-Chlorocarbanilate

Five g. (0.017 mole) of the intermediate product of Example II, 1.65 ml. (0.020 mole) pyridine and 50 ml. acetone were added to a 300 ml. stirred round bottom flask and cooled to a -30.degree. C. in a dry ice acetone bath. 1.45 ml. (0.019 mole) of methyl chloroformate was added with stirring and solution was allowed to reach ambient temperature. About 50 ml. of chloroform was added to the mixture which was then washed sequentially with approximately 100 ml. of water and 100 ml. of sodium bicarbonate. The organic layer was dried over MgSO.sub.4, filtered and rotary evaporated to obtain an oil. The oil was triturated with pentane to crystallize product, yielding 5.3 g. of product having a melting point of from 100.degree. to 104.degree. C. The structure was confirmed by IR and NMR analyses as the title compound. The compound of this example will be referred to as Compound 1.

EXAMPLE IV

4-(Benzo-1,4-Dioxane-2-Methoxy)-3-Chloro-Cyclopropane Carboxanilide

The equipment and procedure as in Example III above were followed with the exceptions that the round bottom flask was originally cooled to -40.degree. C. and that 1.70 ml. (0.019 mole) of cyclopropane carboxylic acid chloride was added to the cooled round bottom flask instead of methylchloroformate. The crystals were formed in the mixture which were filtered off in vacuum and the filter was washed sequentially with water and sodium bicarbonate solution. The organic layer was dried over MgSO.sub.4 and rotary evaporated to obtain crystals which were added to those previously obtained. 5.3 g. of a product having a m.p. of from 144.degree. to 148.degree. C. were produced for a yield of 86.5%. The structure was confirmed by analyses of IR and NMR of the title compound. The compound of this example will be referred to as Compound 2.

EXAMPLE V

4-(Benzo-1,4-Dioxane-2-Methoxy)-3-Chloropropionanilide

The equipment and procedure were the same as Example III with the exceptions that 3.0 g. (0.010 mole) of the intermediate of Example II, 1.67 ml. (0.012 mole) of triethylamine and 50 ml. of dichloromethane were added to the round bottom flask which was then cooled to -40.degree. C. 0.96 ml. (0.011 mole) of propionyl chloride were then added. The reaction mixture was worked up as in Example III and the filtrate was readily evaporated to remove solvent and obtain 3.4 g. of crystalline product having a m.p. of 111.degree.-113.degree. C. in a yield of 97.8%. The structure was confirmed by analyses of IR and NMR as the title compound. The compound of this example will be referred to as Compound 3.

EXAMPLE VI

S-Methyl-4-(Benzo-1,4-Dioxane-2-Methoxy)-3-Chlorothiolcarbanilate

The procedure and reagents were the same as in Example III with the exception that 1.62 ml. (0.019 mole) of methylchlorothioformate was added to the cooled flask instead of the methylchloroformate. The round bottom flask was originally cooled to -35.degree. C. The product was worked up in the same manner with the exception that triturate with pentane was not required. 6.4 g. of crystalline product having a m.p. of 112.degree.-116.degree. C. and at a yield of 102.9% was obtained. The structure was confirmed by analyses of IR and NMR as the title compound. The compound of this example will be referred to as Compound 4.

EXAMPLE VII

1,1-Diemthyl-3-[4-(2-Benzodioxanemethoxy)-3-Chlorophenyl]-Urea

Ten g. (0.035 mole) of the intermediate prepared in Example II and 100 ml. of toluene were combined in a 250 ml. round bottom 4-neck flask and heated to 70.degree. C. with stirring. The stirred solution was saturated with hydrogen chloride gas to give a thick slurry. Phosgene was then added until excess refluxing occurred and the mixture became much more fluid. The mixture was filtered and the filtrate evaporated in vacuo to form an oil that crystallized to give 10 g. of the crystalline isocyanate intermediate having a m.p. of 79.degree.-80.degree. C. The structure was confirmed by analysis of the mass spectra.

Five g. (0.0157 mole) of the above isocyanate intermediate was dissolved in 100 ml. of dry toluene. Into this stirred solution excess dimethylamine was bubbled. The reaction was exothermic to 40.degree. C. The reaction was allowed to cool to room temperature and evaporated in vacuo to yield 4.6 g. of a product having a m.p. of 130.degree.-132.degree. C. The structure was confirmed by analysis of the NMR as the title compound. The compound of this example will be referred to as Compound 7.

EXAMPLE VIII

1-Methyl-1-Methoxy-3-[4-(2-Benzodioxanemethoxy)-3-Chlorophenyl]-Urea

Five g. (0.0157 mole) of the isocyanate intermediate prepared in Example VII was dissolved in 50 ml. of methylene chloride. A mixture of 1.69 g. (0.0173 mole) of O,N-dimethylhydroxylamine hydrochloride and 2.41 ml. (0.0173 mole) of triethylamine in 50 ml. of methylene chloride was added to this solution. The resulting mixture was allowed to stand overnight and was then washed with 100 ml. of water, 50 ml. of 1 N hydrochloric acid and 100 ml. of saturated sodium bicarbonate solution. The mixture was then dried over magnesium sulfate and evaporated in vacuo to yield 4.3 g. of an oil that crystallized on standing. The crystalline product had a m.p. of 91.degree.-92.degree. C. The structure was confirmed by analysis of the NMR. The compound of this example will be referred to as Compound 8.

                  TABLE I
    ______________________________________
     ##STR8##
    Compound                  Physical
    Number     R              Properties
    ______________________________________
    1          OCH.sub.3      m.p. 100-104.degree. C.
                ##STR9##      m.p. 144-148.degree. C.
    3          C.sub.2 H.sub.5
                              m.p. 111-113.degree. C.
    4          SCH.sub.3      m.p. 112-116.degree. C.
    5          NHCH.sub.3     m.p. 150-153.degree. C.
    6          CHClCH.sub.3   m.p. 123-125.degree. C.
    7          N(CH.sub.3).sub.2
                              m.p. 130-132.degree. C.
    8          N(CH.sub.3)OCH.sub.3
                              m.p.  91-92.degree. C.
    9          C(CH.sub.3)CH.sub.2
                              semi-solid
    10         CHCH.sub.2     m.p. 125-127.degree. C.
    11         C(CH.sub.3).sub.3
                              m.p. 119-120.degree. C.
    ______________________________________

                  TABLE II
    ______________________________________
    Compound                                   Average %
    Number  CG     WG     RO   MD   CD   BEAN  Control
    ______________________________________
    1       100    98     30   100  100  100   88
    2       100    70     10   100  100  100   80
    3       100    60     10   100  100  100   78
    4       100    70     30   100  100  100   83
    5        95    40      0   100  100  100   73
    6        10    30      0   100   40   20   33
    7       100    90     80   100  100  100   95
    8       100    90     20   100  100  100   85
    9        30    30     20   100  100  100   63
    10       20    30     20   100  100  100   62
    11       20     0      0   100  100  100   53
    ______________________________________