The following new compounds were prepared from cyanoguanidine or guanylurea as potential flame retardants for cellulosic textiles -2-cyano-1-[bis-(dimethylamino)phosphinyl]guanidine, 2-cyano-1-(diethoxyphosphinyl)guanidine, and 2-carbamoyl-1-(diethoxyphosphinyl) guanidine. The successful phosphorylation of guanylurea required use of a dry, aprotic solvent.

This invention relates to some novel phosphiny-derivatives and to the 
preparation thereof. 
The main object of the instant invention is to provide phosphinylguanidine 
compounds which are useful in flame retardant compositions for cellulosic 
materials such as cotton and rayon. 
A second object of the instant invention is to provide methods of preparing 
new phosphinylguanidine derivatives. 
In the course of investigating compounds containing phosphorus and nitrogen 
as possible flame retardants for textiles, we prepared new compounds Ia-c 
from cyanoguanidine or guanylurea: 
##STR1## 
A search of the literature for compounds with structure I, where Y = CN or 
C(O)NH.sub.2 and Z is alkoxy or aryloxy, revealed that only three such 
cyanoguanidine derivatives (Y = CN) and one such guanylurea derivative (Y 
= C(O)NH.sub.2) have been reported, all of them containing aryloxy groups. 
[Beyer, H., Pyl, T., and Lemke, H., J. Prakt. Chem. 16, 132 (1962)]. Only 
three such aliphatic derivatives of guanidine itself (Y = H) have been 
reported. [Cates, L. A., Ferguson, N. M., J. Pharm. Sci. 55, 966 (1966), 
and Cramer, F., Vollmar, A., Chem. Ber. 91, 911 (1958)]. No references to 
diaminophosphinyl derivatives of guanidine, cyanoguanidine, or guanylurea 
(I, Y = H, CN, or (C(O)NH.sub.2 ; Z = NH.sub.2 or NR.sub.2) could be found 
in the literature. 
Beyer et al. prepared 2-cyano-1-(diaryloxyphosphinyl)guanidines by adding 
the diaryl phosphorochloridate to a solution of 1 mole of cyanoguanidine 
and 2 moles of sodium hydroxide in aqueous acetone. We used this procedure 
to prepare Ia and Ib, but no such phosphorylations or guanylurea have been 
reported. The 2-carbamoyl-1-(diaryloxyphosphinyl)-guanidine reported by 
Beyer et al. was prepared by hydrolysis of the corresponding 
cyanoguanidine. Our attempts to prepare Ic from diethyl 
phosphorochloridate and guanylurea in methanol or in a benzene-water 
mixture gave products from which only guanylurea salts could be isolated. 
The desired product was obtained when a suspension of guanylurea in an 
aprotic solvent was used in the reaction. Ic was isolated in 13% yield 
when acetonitrile was used, and in 46% yield when dry acetone was used 
with precautions to exclude moisture from the system. The higher yield in 
the latter case was probably due to absence of moisture rather than to 
choice of solvent. 
We also prepared Ic by the hydrolysis of the corresponding cyanoguanidine, 
Ib. 
It is obvious in the general formula Z.sub.2 P(O)Cl that Z may be 
NEt.sub.2, NPr.sub.2, etc., or OMe, OPr, etc., in addition to NMe.sub.2 
and OEt used in the preparation of Ia and Ic as described in this 
invention. 
In addition to being useful in flame retardant compositions for cellulosic 
materials, compounds Ia, Ib, and Ic of this invention are useful in the 
synthesis of other compounds. For example, Ib was used in the synthesis of 
Ic as previously stated. 
The compounds of this invention were identified by elemental analyses and 
infrared absorption spectra. 
The invention will be more clearly understood by the following illustrative 
examples.

EXAMPLE 1 
2-Cyano-1-[bis(dimethylamino)phosphinyl]guanidine Ia. 
A solution of 17.1 grams (0.100 mole) of tetramethylphosphorodiamidic 
chloride (5) in 10 ml of dry acetone was added dropwise at 
25.degree.-29.degree. C during 32 min to a stirred solution of 8.4 grams 
(0.100 mole) of cyanoguanidine and 15.8 grams (0.200 mole) of 50.5% 
aqueous sodium hydroxide in a mixture of 50 ml of acetone and 40 ml of 
water. The mixture was stirred for 1 hr longer, then acidified by addition 
of 6.0 grams (0.100 mole) of glacial acetic acid. Addition of a little 
more acetone induced crystallization. The mixture was cooled and filtered 
to obtain 4.3 grams (20%) of crystals. Recrystallization from ethanol gave 
colorless crystals; mp 213.degree. C (with gas evolution). 
Ia is soluble in hot water, slightly soluble in hot ethanol, and 
practically insoluble in 2-propanol, acetone, acetonitrile, and 
chloroform. The ir spectrum showed absorption bands at 2192(s, C=N), 
1630(s, NH.sub.2), 1304(s, CH.sub.3), 1200(s, P=O), 1170(s, CH.sub.3), and 
1064(s, PNC) cm.sup..sup.-1. Anal. Calcd. for C.sub.6 H.sub.15 N.sub.6 OP 
: C, 33.03; H, 6.93; N, 38.52; P, 14.20. Found: C, 33.16; H, 7.10; N, 
38.68; P, 14.19. 
EXAMPLE 2 
2-Cyano-1-(diethoxyphosphinyl)guanidine (Ib) 
A solution of 17.29 grams (0.100 mole) of diethyl phosphorochloridate in 10 
ml of acetone was added dropwise during 37 min to a stirred solution of 
8.41 grams (0.100 mole) of cyanoguanidine and 15.69 grams (0.200 mole) of 
51% aqueous sodium hydroxide in 42 ml of water and 50 ml of acetone. 
During the addition the temperature rose to 47.degree. C and the two 
liquid phases initially present coalesced. The solution was stirred for 30 
min longer and poured into 300 ml of water. Acidification with 17.73 grams 
(0.106 mole) of 36% acetic acid did not lead to separation of a product. 
The solution was evaporated in a stream of air until crystallization was 
observed, then chilled and filtered to obtain 6.54 grams (29.7%) of 
crystals; mp 164.degree.-165.5.degree. C. The product was recrystallized 
from acetone: mp 164.degree.-165.degree. C. 
Ib is soluble in ethanol, 2-ethoxyethanol, hot water, hot 2-propanol, hot 
acetone, and hot acetonitrile, and practically insoluble in chloroform. 
The ir spectrum showed absorption bands at 2214(s, C=N, 1662(s, NH.sub.2), 
1243(s, P=O), 1160(w, POEt), 1044(vs, POC) cm.sup.1. 
Anal. Calcd. for C.sub.6 H.sub.13 N.sub.4 O.sub.3 P: C, 32.73; H, 5.95; N, 
25.45; P, 14.07. Found: C, 32.77; H, 5.96; N, 25.50; P, 14.06. 
EXAMPLE 3 
Reaction of Diethyl Phosphorochloridate with Guanylurea in Methanol. 
A solution of 1.08 grams (0.0200 mole) of sodium methoxide in 10 ml of 
methanol was added to a suspension of 3.02 grams (0.0100 mole) of 
guanylurea sulfate in 35 ml of methanol. The mixture was stirred for 2 hr, 
heated to boiling, allowed to cool to 45.degree. C, and filtered to remove 
sodium sulfate. 
Triethylamine (2.09 grams, 0.0207 mole) was added to the guanylurea 
solution, then a solution of 3.47 grams (0.0201 mole) of diethyl 
phosphorochloridate in 5 ml of acetone was added dropwise during 5 min as 
the temperature rose to 41.degree. C. The mixture was stirred 30 min and 
allowed to stand overnight. Solvent was removed on a rotary evaporator and 
the residue was washed twice with chloroform to remove triethylamine 
hydrochloride. This left 1.94 grams (70%) of guanylurea hydrochloride, 
which was recrystallized from ethanol and identified by elemental 
analyses, ir, and qualitative tests for guanylurea (Ni complex formation) 
and chloride ion. Since this method was not successful the following 
method was used. 
2-Carbamoyl-1-(diethoxyphosphinyl)guanidine (Ic) 
A. From Guanylurea -- A solution of guanylurea in methanol was prepared 
essentially as described above and solvent was removed on a rotary 
evaporator. Recrystallization of the residue from ethanol gave guanylurea 
in 75% yield. 
Under a nitrogen atmosphere 5.64 grams (0.0552 mole) of guanylurea, 85 ml 
of dry acetone, and 5.97 grams (0.0552 mole) of guanylurea, 85 ml of dry 
acetone, and 5.97 grams (0.0590 mole) of triethylamine were placed in a 
200-ml flask equipped with a mechanical stirrer, a thermometer, a dropping 
funnel, a nitrogen inlet, and a drying tube. A solution of 9.53 grams 
(0.0552 mole) of diethyl phosphorochloridate in 10 ml of acetone was added 
dropwise to the stirred suspension during 13 min. The flask was cooled 
intermittently in an ice bath to hold the temperature at 
27.degree.-30.degree. C. The suspension was stirred for 2 hr longer, 
allowed to stand overnight, and filtered. The residue was washed with 
acetone and recrystallized from chloroform to obtain 2.61 grams of 
crystals; mp 164.degree.-165.degree. C (cloudy melt). More Ic was isolated 
from the mother liquor and the acetone solution; the total yield of 
material with mp above 164.degree. was 6.08 grams (46.2%). The mp of Ic 
prepared from granylurea was not depressed on mixture with Ic prepared by 
hydrolysis of Ib. 
B. From Ib -- A mixture of 4.40 grams (0.0200 mole) of Ib, 1.91 grams of 
38% hydrochloric acid, and 60 ml of ethanol was stirred and heated under 
reflux for 30 min, then evaporated overnight in a stream of air. The 
residual paste was stirred with acetone and filtered. The unidentified 
acetone-insoluble material, mp 257.degree.-260.degree. C, weighed 0.18 
gram. The acetone solution was evaporated, water was added, and the 
resulting crystals were collected and recrystallized from methanol to 
obtain 0.30 gram (7%) of Ib, mp 161.degree.-163.degree. C. Crystals 
obtained from the two mother liquors were combined and recrystallized from 
water and from acetone to obtain 0.28 gram (6%) of Ic; mp 
164.5.degree.-165.degree. C (cloudy melt, solidifying at higher 
temperatures and remelting near 245.degree. C). The analytical sample was 
recrystallized from acetone: mp 170.degree.-170.5.degree. C (cloudy melt). 
Increasing the reaction time to 3 hr did not increase the amount of Ic 
isolated, but in this case no Ib was recovered. The unidentified 
acetone-insoluble product was again isolated in low yield. 
Ic is soluble in 2-ethoxyethanol, warm ethanol, hot water, and hot 
2-propanol, slightly soluble in hot acetone and hot acetonitrile, and 
practically insoluble in chloroform. The ir spectrum showed absorption 
bands at 3406(s, NH), 3315(m, NH), 1202(s, P=O), 1165(w, POEt), 1024(s, 
POC)cm.sup..sup.-1. 
Anal. Calcd. for C.sub.6 H.sub.15 N.sub.4 O.sub.4 P: C, 30.26; H, 6.35; N, 
23.52; P, 13.00. Found: C, 30.43; H, 6.40; N, 23.60; P, 13.16. 
EXAMPLE 4 
Cotton Fabric Treatment 
Dimethylformamide (DMF) solutions of compounds 1a, 1b, and 1c in Examples 
1, 2, and 3 were prepared in concentrations of 10%, 20%, and 20% (by 
weight), respectively. It was necessary to warm the DMF to dissolve 1a. 
Samples of cotton flannelete were impregnated with each solution, and each 
sample was dried for 5 minutes at 85.degree. C. The samples treated with 
1a, 1b, and 1c had Strip Flame Test angles for flame retardancy of 
90.degree., 135.degree., and 135.degree., respectively. An angle of 
90.degree. indicates fair flame-retardancy, and 135.degree. indicates good 
flame-retardancy. The Strip Flame Test was performed by the method of W. 
A. Reeves, et al., Textile Research Journal 23, 527 (1953).