IE48999B1

IE48999B1 - Urethane derivatives

Info

Publication number: IE48999B1
Application number: IE2287/79A
Authority: IE
Original assignee: Hoffmann La Roche
Priority date: 1978-11-29
Filing date: 1979-11-28
Publication date: 1985-07-10
Also published as: ATE2081T1; KE3322A; EP0011859B1; GB2036741B; GB2036741A; PH16764A; IE792287L; MY8400342A; ES486399A0; NZ192228A; ES8100255A1; HK70283A; NO152134C; NO152134B; CA1128505A; AU531276B2; AU5272879A; FI66386B; DE2964383D1; FI793705A

Abstract

Urethane derivatives of the formula <IMAGE> wherein R<1> is aryl, alkylaryl, haloaryl, nitroaryl, alkoxyaryl, aryloxyaryl acylaryl, alkyl, cycloalkyl, arylalkyl, haloarylalkyl or arylcycloalkyl and R<2> is methyl or ethyl, and their pharmaceutically acceptable salts. Moreover, the manufacture of the above urethane derivatives as well as compositions containing same. Also the use of these derivatives for the treatment or prophylaxis of diseases and to promote animal growth.

Description

The present invention relates to urethane derivatives of the general formula wherein is phenyl, C^_^-alkyl-phenyl, halogen-phenyl, nitro-phenyl, phenoxy-phenyl, C^_7alkyl, cycloalkyl, phenyl-C1_7-alkyl, C^_7~alkanoyl-phenyl, C1_7~alkoxyphenyl or phenyl-C, ..-cycloalkyl and 2 R is methyl or ethyl, and their pharmaceutically acceptable salts.

The shorthand expression Me is utilized throughout to represent methyl.

The compounds of the present invention and their salts exhibit activity as antibacterial agents, growth promoting agents in ruminants and monogastric animals which ferment fibrous vegetable matter in the cecum, coccidiostats, antihypertensives, antimalarial agents and as agents in the treatment of swine dysentery. - 3 48998 By the term acyl is meant a to C?, preferably a C1 to Cjj alkanoic acid moiety, i.e., radicals of the formula R—C — II wherein R is C1 to Cg alkyl or hydrogen, e.g., acetyl, propionyl, butyryl and the like.

By the term alkoxy is meant a to Cy lower alkyl group having an oxygen function substituted therein, such as methoxy, ethoxy, n-propoxy and the like.

The term aryl denotes an aromatic residue derived by the removal of a hydrogen atom from an aromatic hydrocarbon, such as, for example, phenyl, pyridyl or furyl, especially phenyl. Thereafter the aryl residue may be substituted by various groups. A substituent on a phenyl nucleus is preferably in 4-position such as in 4-alkylaryl, e.g. 4-methylphenyl (4-tolyl), 4-halophenyl, e.g. 4-ehlorophenyl, 4-nitrophenyl, 4-aryloxy aryl, e.g. 4-phenoxyphenyl, 4-alkoxyphenyl, e.g. 4-methoxyphenyl, 4-(alkanoyl)-phenyl, e.g. 4-acetyl-phenyl or in 4-(benzoyl)-phenyl.

By the term alkyl is meant a C1 to Cy straight or branched chain hydrocarbon, preferably a to hydrocarbon, such as methyl, ethyl, n-propyl, isopropyl, n-butyl. The alkyl group may be substituted by an aryl residue as defined hereinbefore to form an arylalkyl residue, e.g. 1-phenylethyl, 2-phenylethyl (phenethyl), or by a haloaryl residue as defined hereinbefore to form a haloarylalkyl residue, e.g. 4-bromophenethyl.

By the term eyeloalkyi is meant cyclic hydrocarbon groups containing from 3 to 7 carbon atoms, such as eyclopropyl, cyclobutyl, cyclohexyl and the like with - 4 cyclohexyl as preferred. The cycloalkyl group may be substituted by an aryl residue as defined hereinbefore to form an arylcycloalkyl residue, e.g. 2-(phenyl)cyclopropyl.

Certain of the urethane derivatives, viz. those of li formula I wherein R is phenethyl and their pharmaceutically acceptable salts, are produced by Streptomyces organisms designated as species X-14667, X-14573 and X-14575. Streptomyces sp. X-14667 was isolated from a soil sample collected from Aesculapius temple, Epidaurus, Greece. Streptomyces sp. X-14573 was isolated from a soil sample collected at the University of Arizona, Tempe, Arizona. Streptomyces sp. X-14575 was isolated from a soil sample collected in a corn field in the Cats15 kills, New York. Streptomyces sp. X-14667, X-14573 and X-14575 were deposited with the United States Department of Agriculture, Agricultural Research Service, Northern Regional Research Laboratories (NRRL) Peoria, Illinois, USA as lyophilized vials of the cultures. The cultures, given the identification numbers NRRL 11336 (X-14667), NRRL 11337 (X-14573) and NRRL 11338 (X-14575) were all deposited at NRRL on June 29, 1978. Subcultures thereof have been deposited on August 23, 1979, as lyophilized vials at American Type Culture Collection, Rockville, Maryland, USA and been given the identification numbers ATCC 31551 (X-14667), ATCC 31552 (X-14573) and ATCC 31553 (X-14575) by ATCC.

The urethane derivatives are polyether antibiotics and form a variety of pharmaceutically acceptable salts.

These salts are prepared from the free acid form of the antibiotics by methods well-known for compounds of the polyether type in the art; for example, by washing the free acid in solution with a suitable base or salt. Examples of such pharmaceutically acceptable basic substan35 ces capable of forming salts for the purpose of the pre48999 - 5 sent Invention include alkali metal bases, such as sodium hydroxide, potassium hydroxide, lithium hydroxide and the like; alkaline earth metal bases, such as calcium hydroxide, barium hydroxide and the like; and ammonium hydroxide. Alkali metal or alkaline earth salts suitable for forming pharmaceutically acceptable salts can include anions such as carbonates, bicarbonates and sulfates.

Examples of organic bases forming pharmaceutically acceptable salts with the polyether compounds are lower alkyl amines, primary, secondary and tertiary hydroxy lower alkylamines such as ethylamine, isopropylamine, diethylamine, methyl-n-butylamine, ethanolamine and diethanolamine.

An amine especially preferred is N-methylglucamine. Salts of N-methylgluoamine are of special value because of their water-solubility which makes them amenable to parenteral use.

MORPHOLOGICAL CHARACTERISTICS Representative strains of Streptomyces sp. X—14667, X—14573 and X—14575 have the following characteristics: Sodium chloride tolerance, hydrolysis of casein and reduction of nitrate were determined by the methods recommended by Gordon and Smith, J. Bacteriol., 66, 41—48, 1953· Starch hydrolysis was determined after growth on agar of Actinomyces broth (Difco) with 0.25 o/o soluble starch, and was tested by flooding the plates with iodine-KI solution. Gelatin hydrolysis was tested according to Skerman, (A Guide to Identification of the Genera of Bacteria, The Williams and Wilkins Co., Baltimore, 1967) using Actinomyces broth (Difco) with 2 0/0 agar in place of meat infusion agar. All tests were run at 28°C. - 6 The standard ISP media of Shirling and Gottlieb were used for the description of growth and pigmentation (color determinations were made after two weeks of incubation at 28°C). Carbon utilization was also determined by the method of Shirling and Gottlieb (Int. J. Syst. Bacteriol., 1_6, 313-340, 1966). A 24 hour old ISP-1 broth culture was homogenized and centrifuged to obtain a washed suspension for inoculation. The ability of the organism to grow at 10, 28, 37, 45 and 50°C was investigated by inoculating broth of ISP-1 (Difco) medium. Cell wall analysis was performed by the method of Becker et al. (Applied Microbiol. 12, 421-423, 1964).

Microscopic examination. Streptomyces sp. X-14667, X—14573 and X-14575 produce a substrate mycelium which does not fragment into spores, and an aerial mycelium, which later forms spore chains. After 14 days of incubation at 28°C, the spore chains appear rectusflexibilis in form with greater than 50 spores per chain. Spores are smooth and range in size from 0.70 by 0.5 pm to 1.35 by 0.38 pm for X-14667; 0.7 by 0.4 to 1.45 by 0.4 pm for X—14573; 0.8 by 0.5 pm to 0.6 by 1.0 pm for X-14575.

The cell wall of the cultures contains the LL isomer of diaminopimelic acid, which, together with the above characteristics, places these organisms in the genus Strep tomyees (Lechevalier et al., Adv. Appl. Microbiol., 14, 47-72, 1971).

Macroscopic examination. In Tables 1, 2 and 3 are summarized the amount of growth, degree of sporulation, spore mass color, color of reverse substrate mycelium, and presence of a soluble pigment produced by Streptomyces sp. X-14667, X-14573 and X-14575 on various solid media. - 7 48999 00 •rl « in β β σ\ g H •9 <« - «Η FQ d Ο Φ β m Xl P Ο •Η ώ d* Ρ β d •rl β γΗ rH ο β d Pi •rl 3 β X? β Ο CQ d ο S « f* Ρ β ο o φ a •ο β Ο d β K ΡΜ β 03 o Φ H ϋ O £ o a ο +3 kO d M H X) * φ o •rl Η p I +3 cn o H O KA 'X’f P CQ >3 co ω xl p a o β «Η β Φ Λ1 d P P d XJ P co § d Φ CQ Φ a 0) XJ o co β o H O o Φ Xj EH CO P P Φ β P CQ cti a o •rl s P β Φ X! P >3 Xl d Φ d β o Φ β ¢0 •H d Φ d Φ d d d Ώ d β d Εώ d V. in r~l Xi o •rl £ o P xi p o β X» M o Q I Λ4 G) Pi d N O TABLE 2. CULTURAL CHARACTERISTICS 0? o · ft o fc tifl O flj o o fd fc X} ο o rt * •rl flj cd υ Ρ ·Η rt fc ο ω o a GO in cn rd M3 rd O *4· tn * I yjtn rt rd •rl tn H * fcvo H rdl Xl · CQ r-d O • Ή -P fc Ο d d -P •f"5 o O flj fc ft ft · -p ra *d >> d CQ *d • *d Ho flj ft fc 0) flJ tio rd Ή _ flj rd flj rt -p o -PU rl o in -p o · OJ · rd rt ft , fc Xt Φ $ o -p · «rl o Λ •P >> ft 'd d tJ rt d o o d fc nJ •id *d .d ft ft ft xl -p o fc xi o ft I Λ1 d ft d (S3 O CD ·γΙ to H S CD CD O i> £> ω P CO ft o ϋ o Xi O si ft •SI tn § P g o o •SI Sjid 0) ii ft ca P P o o P · (73 *·£> • cn ft ft P O Si κ cn * ι Atn 03 ft •h cn ft * PW pftl o · O ft . o TABLE 5- CU1TURAI CHARACTERISTICS OF STRSFTOHYOSS SF. X-14575 p o ft o ϋ ω d ϊ£ ω p o A 0Q P ft Χί ί p +3 tb o P| P ft id 0) P tb o X»| P •rl P +3 ω o sl Φ β kA ·* ¢0 O £ ·- Qj •rl ft^ too ftjP A ra rd -Ρ -Ρ Ή ca -P S -ri £ -p ra H 45 u 45 O 2 £ Φ > was -p P •ri OSS o H'' Pl ® iri a cn^ ρ ·η ft o id * to 03 * ca · p ft o ft o φ ·η · ca XS ft ft Ao* ρ to *Φ * P ca ft * O ft ft id id ft 03 xi " co CQ P 3 I 03 P P fb O Ο O A 03 P o ft P ·- CJ xift P P £ p o o ρ A O CO 3 p o to a v < A P (0 ft £ ·* O XI P P Ρ X> P o P P CJ to «4 φ 03 P P 03 ca tO CQ ft p ii 03 A φ 0) N ti ft ft >ift o o ft o a a O CQ Xl -P p ♦-ft A A tb ω -P Xi ft > s O ··» |3 s Q •s N £ P ft tb 0) ti ca ft xi ¥ o id P Χί ¥ o . β O ft to o to O S 45 to o to o ft A ft •ri 4=1 ft •rl P Φ P 03 •P 03 P Φ P CO 03 P co P s ·»-ρ P <0 P ¢0 ft ft ca ft ca ri 45 S ca ft ca ft ti A id p id SO® id P id a il P o> P φ s s a 03 id 03 id O ft ft o ft osw ft o ft o A O o A o Pt-P -ri o A o A CQ 03 a CQ a ra m Pi a CQ a CQ P ϋ d id P tn I ft ω ι 03Q P ft Cj i ω ft co C3 ft caA ft cm ca S 45 P 1 03 to o 03 Pd a id id CO CO P o ca 03 ft CO P P ft' o ft 03 ti •rl to Ctf id «0 ft ω £ΰ ftX> O ' id in 03 ι o ft >3 co ft ft CiJ o X o A I AS 0) ft ca co o ca M id o ft o o xi p a o i< p ti φ s P P ca xi p (/3 ca £ ft ii £1 Xi o CQ id o ft o o xi EH nJ ft · O P o ii 03 O ’«-3 ft o P id co Pd id O 03 Α φ: id ϋ ο £ o a1 o P Pl id p cq ft ca ti o ft p aj P P P β xi p £ ft ft P id ca to ca in xi o ft i o P A ft PP xi p o id A M o A I A ca « o o - 10 Physiological characteristics. Tables 4 and 5 report the results of carbon utilization and metabolic characteristics of Streptomyces sp. X-14667, X-14573 and X-14575 and compares the results with those of 5. cinnamonensls, 1712A which produces monensin.

TABLE 4. Comparison of carbon utilization of Streptomyces sp. X-14667, X-14573, X-14575 and S. cinnamonensls 1712A.

Growth response* of: Carbon S. cinnamonensis Source X-14667 X-14573 X-14575 1712A D-Glucose ++ ++ ++ D-Xylose + ++ ++ ++ L-Arabinose ++ ++ ++ +(+) L-Rhamnose - ++ - ++ D-Fructose +(+) ++ ++ ++ D-Galactose ++ ++ ++ ++ Raffinose ++ +(+) ++ +(+) D-Manni tol ++ ++ ++ ++ i-Inositol + ++ ++ ++ Salicin —to+ ++ ++ +(+) Sucrose - - - - Cellulose - - - - * -, Negative ! response i; i, doubtful response; +, more growth than on carbon control I tut less than on glucose; ++, positive response equal to the amount of growth on glucose. 48939 -11 TAB I,Μ 5 METABOLIC CHARACTERISTICS Test X-14667 X-14573 X-14575 S.oinnamonensis 1712A ISP-6 darkening - - - - Melanin, ISP-7 - - - . - Casein hydrolysis + + + + ί Gelatin hydrolysis + + + + , Starch hydrolysis + + 4- + NaCl (%'} tolerance <10, probably = 7% 7 7 <10 ’ Growth range temp. ' (°C) 10-37 10-37; ISP-1 darkening - + , redwood + slightly brownish + slight , Reverse-side pigment slightly red-brown brown brown, occasionally brownish occasional# . Soluble pigment 1 pink; reversible to blue with NaOH red-brown brown brownish Antibiotic production monensin A and B and the corresponding phenethylurethanes monensin A and B 1 Nitrate reduction + + + + in 2 weeks Hygroscopic property slight on ISP-5 A comparison of the description of Streptomyces sp. X-14667, X—14573 and X-14575 with those of the Streptomyces species described in Bergey's Manual (Buchanan and Gibbons, ed., Bergey's Manual of Determinative Bacteriology, 8th 5 ed., 748-829, 1974), H. Nonomura's key for classification (J. Ferment. Technol., 52, 78-92, 1974) and Pridham and Lyons' classification (Dev. Ind. Microbiol. 10, 183— 221, 1969), showed that S. cinnamonensis is the closest relative to the above strains based on the following com1° bination of criteria: gray spore mass color, rectus-flexibilis spore chain form, smooth spore surface, ohromogenic reaction on ISP media 1 and 6, and carbon utilization characteristics. S. cinnamonensis is similar to X14667, X-14573 and X-14575 in that they all produce monen15 sin A and monensin B. However, S. cinnamonensis, differs from the above organisms since it does not produce any of the monensin phenethylurethanes.

The Streptomyces species X-14667, X-14573 and X14575 described herein include all strains of Strepto20 myees which form the monensin phenethylurethanes of the present invention and which cannot be definitely differentiated from the strains NRRL 11336 (ATCC 31551), NRRL 11337 (ATCC 31552) and NRRL 11338 (ATCC 31553) and their subcultures including mutants and variants. The claimed compounds are described herein and after this identification is known, it is easy to differentiate the strains producing these compounds from others.

Streptomyces X-14667, X-14573 and X-14575 when grown under suitable conditions produces monensin urethane deri30 vatives. A fermentation broth containing Streptomyces X-14667, X—14573 or X-14575 is prepared by inoculating spores or mycelia of the organism producing the derivatives into a suitable medium and then cultivating under aerobic conditions. For the production of the derivatives, cultivation on a solid medium is possible but for produ48999 - 13 cing in large quantities, cultivation in a liquid medium is preferable. The temperature of cultivation may be varied over a wide range, 2O°-35°C, within which the organism may grow but a temperature of 26°-30°C and a substantially neutral pH are preferred. In the submerged aerobic fermentation of the organism for the production of the monensin derivatives, the medium may contain as the source for carbon a commercially available glyceride oil or a carbohydrate such as glycerol, glucose, maltose, lactose, dextrin, starch etc. in pure or crude states and a3 the source of nitrogen an organic material such as soybean meal, distillers’ solubles, peanut meal, cotton seed meal, meat extract, peptone, fish meal, yeast extract, corn steep liquor etc. and when desired inorganic sources of nitrogen such as nitrates and ammonium salts and mineral salts such as ammonium sulfate, magnesium sulfate and the like. It also may contain sodium chloride, potassium chloride, potassium phosphate and the like and buffering agents such a3 sodium citrate, calcium carbonate or phosphates and trace amounts of heavy metal salts. In aerated submerged culturing procedures an anti-foam agent such as liquid paraffin, fatty oils or silicone compounds is used. More than one kind of carbon source, nitrogen source or anti-foam source may be used for production of the monensin derivatives.

The antibiotic activity of the urethane derivatives is illustrated by the following table (Table 6): 8999 1 □ -Ί -I P « O o O J d ill V © P -7) r >. r » u > cu O\ -d (Ο to rd rd rd H IO eo io 03 to to Ό 1 (U eo vo rd to to IO to tO to Ό O r-f IO r-f o « a. cs a i o rd eo ρ -□ -d rd •J O 4) IO , : ο o to IO rd to CO □ Ρ © □ O <-t m >> C! -C tn < m ahi eo j-teo Ό flO rd cd rd rd to to to to . (O «3 £ \o CU -.ύ r-l O to to IO to to to rd r-l to rd 3 -i 6-. rl UD Q · CO Cl Ρ. ΓΟΟ) cu H - HO 0 o a co Q H as d tt h w ^^t^totoO'Qtrcjcocj K’ d r4 ο o d odooOOHoooo 0) 0) —1 i—1 - P Q| o jj eo k· 3 t> fi o· m vp -o CD 'C -t .ι-ιηΙΏΟΟ’Γ'Χ'ί-’Ι·®'/ r‘ 4 rid o d odddHOrtOQOO 3 -. f,, Qi υ · <Ό :: P· r- Q ω cu tn cm tn ζ4 £ so CD V rd Ο O OWOl^-tOfUCUhfOr-IO 4 J o d d o dddodoodooo 2 ., 3 0.-1-. u a ο ό Ρ ϋ a> Ί r, ο ρ © ,-p CD CM rd O rdrdrd£UtO -· < £}' . vo . 1 VO CM CU (D al <50 cn VO to uJ· CM to • a 1 o. u- tn p eo 1 3 to -rv to IO VO ω *P © to to rd ϋ vo Μ- v U3 V d d tO rd r_> O OrdrdfOCMrdrdOOHO rd Φ t; P· . (0 fi i4 (4 il r, j? § ι § $ S A ι o ·:, s s λ - ι b s ι s g, • rd fi C* L* © Λ P >» «-. P © £ I fi I M r-.'H φ φ .fi Ρ* ©1 MrdOHrd+’ Sjgjj l X4 i4 X4 Ο. O PO©>>(uH3>j^K^Hrd * ♦> η ρ. ρ. o J, 3 fi .fi ** fi 3 d 3 2 S' 2 £? v oj mj ι | a ο ηοο©3η^ρ3«ο.«λ β» m » ι ρ λ ti -ι o a +3 js α α fi λ ο © © - CO. - ii ο ® Μ ί, Λ t— m Ρ o u.' 5 O« (0 dd OfllR© v . Λ »> crta, m ν 1 1 Λ 1 § © ' k 2 i · _d 1 fi -L ‘ fi ' fi - v. pi: _ τ: — r <- o· df ω n 3 ϋ c v-S. v " v ** cj ** a u-O · Αύ . . .*? . k ·. - 3 - *rd » · rl , rt · * £ - -d .·: r,, a) _i« m ;· < < «c+Σ < -<>»««< 4J. -»;+»«? < p p 0 5( c u> r· ,. *' co iC?ifi®flOCCC4fiSc®CiiRh '- »» rl i: t> -ri I -rl t, d c -rl C d-d2-riC-rl5» fi Λ fi O fi fi fiOfi>,fi.fifi>>fi4b • H i]> *· a φ ς, jj o+j atfi©P©fi©s ’ P fi d P r' jc CC fi© fi© CG©fi©fiOfififi’3fi®fi?’fi?iSS • β» Ο Ρ Φ q £ o+j Ol. Op Ο O k ο 1] O >1 Ο Ο O 4 ο Λ O Ο Λ OX » »i 4 -: :< 4| 4-4 φ 4ϊ4 4) ti Pi ti K K A >4 3 ϊ; C! K Ξ E "UPtEfiKCXSfi* (a) Lowest tv.o-fold dilution giving sone of inhibition, in the agwr well diffusion assay. (b) NRRL collection number, all the rest are ATCC numbers. - 15 4899s From the above Table 6 which indicates the in vitro activity of the compounds of the present invention against certain gram-positive bacteria there is found the utility as an antibacterial agent useful in wash solutions for sanitary purposes as in the washing of hands and the cleaning of equipment, floors or furnishings of contaminated rooms or laboratories.

Further, it has been found that certain of the urethane derivatives presently disclosed, viz. those of foro mula I wherein R is aryl, haloaryl, nitroaryl, alkylaryl or cycloalkyl and their pharmaceutically acceptable salts exhibit anti-coecidal activity versus the organism Eimeria tenella.

This anti-coccidal activity is demonstrated on laboratory chickens as follows: Test method.-This test utilizes ten chickens per drug group. Ten chickens are employed as a weight control and ten chickens as an infected control. The drug is given 48 hours in advance of the infection. One gm. of the test drug is mixed in a mechanical mixer with a sufficient amount of chicken feed to result in the desired dosage. The infection consists or approximately 200,000 oocysts orally by pipette. The tests lasts for eleven days and then the surviving birds are autopsied and examined for gross lesions in the ceca. The test birds are rated according to the number of survivors and the number of ceeal lesions. The results are expressed as average degree of infection (A.D.I.). An average degree of infection of less than 2.5 is considered to be significant.

- IS Table 7 Anti-coccidal effects of monensin urethanes added to the feed of chickens infected with Eimeria tenella.

Compound Dosage Average Degree in of Infection feed, (ADI) ppm Uninfected untreated control Infected untreated control none none 0.0 3.0 Monensin A, 4-nitrophenylurethane- 75 0.5 Monensin A, 4-bromophenylurethane 75 0.7 Monensin A, phenylurethane 75 0.9 Monensin A, 4-chlorophenylurethane 65 0.8 Monensin A, 4-methylphenylurethane 75 1.1 Monensin A, 4-iodophenylurethane 125 0.1 Monensin A, 4-fluorophenylurethane 125 1.0 Monensin A, cyclohexylurethane 125 0.8 - 17 The urethane derivatives of the invention have also been found to be active against Treponema hyodysenteriae. The minimal inhibitory concentration of the urethane derivatives is as follows: Compound MIC (mcg/ml) Monensin B, phenethylurethane 0.4-2.0 (prepared from fermentation) Monensin B, phenethylurethane 2.0 (synthetic product) Monensin A, Monensin B, Monensin A, Monensin A, Monensin A, Monensin B, Monensin A, Monensin A, Monensin A, 4-bromophenylurethane (R) -1-phenylethylurethane phenethylurethane phenylurethane 4-chlorophenylurethane (S) -1-phenylethylurethane cyclohexylurethane 2-(pheny1)-eyclopropylurethane 4-fluorophenylurethane 0.4 0.4 0.4 0.08-0.4 0.08 0.4 0.4 0.4 0.08 Testing for activity against Treponema hyodysenteriae, a cause of swine dysentery, consisted of inoculation of blood agar plates containing a series of two or fourfold dilutions of the urethane derivatives with tenfold dilutions of the T. hyodysenteriae strain. After 48 hours of incubation at 42°C in an anerobic atmosphere, Minimum Inhibitory Concentrations were recorded as the lowest concentrations of compound which completely inhibited the most dilute inoculum of each T. hyodysenteriae strain.

The urethane derivatives have further been found to exhibit activity as growth promotants in ruminants. - 18 Administration of the urethane derivatives, hereafter Antibiotics or Antibiotic Compounds, prevents and treats ketosis as well as improves feed utilization in ruminants or swine. The causative mechanism of ketosis is a deficient production of propionate compounds. A presently recommended treatment is administration of propionic acid or feeds which preferentially produce propionates.

It is obvious that encouraging propionate production from ordinary feeds will reduce incidence of ketosis.

It has been found that the urethane derivatives increase the efficiency of feed utilization in ruminant animals when it is administered orally to the animals.

The easiest way to administer the antibiotic is by mixing it in the animal's feed.

However, the antibiotic can be usefully administered in other ways. For example, they can be incorporated into tablets, drenches, boluses, or capsules and dosed to the animals. Formulation of the antibiotic compounds in such dosage forms can be accomplished by means of methods well 2o known in the veterinary pharmaceutical art.

Capsules are readily produced by filling gelatin capsules with any desired form of the desired antibiotic. If desired, the antibiotics can be diluted with an inert powdered diluent, such as a sugar, starch, or puri25 fied crystalline cellulose in order to increase their volume for convenience in filling capsules.

Tablets of the antibiotics are made by conventional pharmaceutical processes. In addition fco the active ingredient a tablet usually contains a base, a disinte30 grator, an absorbent, a binder, and a lubricant. Typical bases include lactose, fine icing sugar, sodium chloride, starch and mannitol. Starch is also a good disintegrator as is alginic acid. Surface active agents such as sodium lauryl sulfate and dioctyl sodium sulphosuccinate are also sometimes used. Commonly used absorbents again include starch and lactose while magnesium carbonate is also useful for oily substance. Frequently used binders are gelatin, gums, starch, dextrin and various cellulose derivatives. Among the commonly used lubricants are magnesium stearate, talc, paraffin wax, various metallic soaps, and polyethylene glycol.

The administration of the antibiotic compounds may be as a slow-pay-out bolus. Such boluses are made as tablets except that a means to delay the dissolution of the antibiotics is provided. Boluses are made to release for lengthy periods. The slow dissolution is assisted by choosing a highly water-insoluble form of the antibiotics.

A substance such as iron filing is added to raise the density of the bolus and keep it static on the bottom of the rumen.

Dissolution of the antibiotics is delayed by use of a matrix of insoluble materials in which the drug is imbedded. For example, substances such as vegetable waxes, purified mineral waxes and water-insoluble polymeric materials are useful.

Drenches of the antibiotics are prepared most easily by choosing a water-soluble form of the antibiotic. If an insoluble form is desired for some reason, a suspension may be made. Alternatively, a drench may be formulated as a solution in a physiologically acceptable solvent such as a polyethylene glycol.

Suspensions of insoluble forms of the antibiotics can be prepared in nonsolvent3 such as vegetable oils such as peanut, corn, or sesame oil, in a glycol such as propylene glycol or a polyether glycol; or in water, depending on the form of the antibiotics chosen. - 20 Suitable physiologically acceptable adjuvants are necessary in order to keep the antibiotics suspended.

The adjuvants can be chosen from among the thickeners, such as carboxymethylcellulose, polyvinylpyrrolidone, gelatin, and the alginates. Many classes of surfactants serve to suspend the antibiotics. For example, lecithin, alkylphenol/polyethylene oxide adducts, naphthalenesulfonates, alkylbenzenesulfonates, and the polyoxyethylene sorbitan esters are useful for making suspensions in li10 quid nonsolvents.

In addition many substances which affect the hydrophilicity, density and surface tension of the liquid can assist in making suspensions in individual cases. For example, silicone anti-foams, glycols, sorbitol and sugars can be useful suspending agents.

The suspendable antibiotics may be offered to the grower as a suspension or as a dry mixture of the antibiotics and adjuvants to be diluted before use.

The antibiotics may also be administered in the drin2o king water of the ruminants. Incorporation into drinking water is performed by adding a water-soluble or watersuspendable form of the antibiotics to the water in the proper amount. Formulation of the antibiotics for addition to drinking water follows the same principles as formulation of drenches.

The most practical way to treat animals with the antibiotic compounds is by the formulation of the compounds into the feed supply. Any type of feed may be medicated with the antibiotic compounds, including common dry feeds, liquid feeds, and pelleted feeds.

The methods of formulating drugs into animal feeds are well-known. It is usual to make a concentrated drug - 21 premix as a raw material for medicated feeds. For example, typical drug preraixes may contain from about one to about 400 grams of drug per pound of premix. The wide range results from the wide range of concentration of drug which may be desired in the final feed. Premixes may be either liquid or solid.

The formulation of ruminant feeds containing the proper amounts of antibiotics for useful treatment is well understood. It is necessary only to calculate the amount of compounds which it is desired to administer to each animal, to take into account the amount of feed per day which the animal eats and the concentration of antibiotic compounds in the premix to be used, and calculate the proper concentration of antibiotic compounds, or of premix, in the feed.

All of the methods of formulating, mixing and pelleting feeds which are normally used in the ruminant feed art are entirely appropriate for manufacturing feeds containing the antibiotic compounds.

As has been shown, oral administration of the antibiotic beneficially alters the production of propionates relative to fhe production of acetates in the rumen. It may therefore be postulated that the same treatment would also benefit monogastric animals which ferment fibrous vegetable matter in the cecum since it would be expected that a beneficial change in the propionate/acetate ration would occur upon oral administration of the instant antibiotics. Horses, swine and rabbits are examplary animals which digest a part of their food by cecal fermentation. 48υ99 Determination of volatile fatty acid (VFA) production A bovine, surgically modified with a rumen fistula, is used as a source of rumen fluid. The integrity of the rumen is maintained by a rumen cannula which is opened in order to obtain rumen fluid samples. The animal is fed twice daily an 80 o/o concentrate (mainly yellow corn with soybean oil meal and alfalfa meal added): 20 o/o roughage ration. The rumen fluid is obtained prior to the morning feeding. The rumen fluid is strained through 4 layers of cheesecloth into a 1 gallon container and is kept under anaerobe quality C02· One thousand mis of the strained rumen fluid are added to 2000 mis of an ice cold buffer having the following composition: Na2HPO4 0.316 g/1 MgSO4 0.112 kh2po4 0.152 CaCl2 0.038 NaHCO^ 2.260 FeSO4-7H2O 0.008 NaCl 0.375 ZnS04.7H20 0.004 KC1 0.375 CuSO^.S^O 0.002 The buffered rumen fluid is held in a 4 liter sepa20 ratory funnel. In order to help maintain the anaerobic character of the rumen fluid and the homogeneity of the buffered rumen fluid, anaerobe quality CO., is bubbled constantly through the fluid in a separatory funnel beginning approximately 1 cm above the separatory funnel stopcock.

Two hundred and fifty ml Erlenmeyer flasks are used for individual fermentations. Each flask to which a compound will be added contains one gram of a finely ground 80 o/o concentrate: 20 o/o alfalfa hay ration. Flasks which are to be used as drug-free controls contain 1.07 grams of the finely ground ration. One ml solution of test compound dissolved in an appropriate solvent is added to each flask and allowed to sit for 1/2 to 1 hour. Each - 23 compound is examined in duplicate flasks at a final concentration of 50 ppm. Solvent without test compound is added to drug-free control fermentation flasks. Monensin at 10 and 50 ppm is used as a positive control in all fermentations.

Eighty grams of buffered rumen fluid are added to each flask containing test compound and 85.93 grams are added to control flasks. Flasks to which all components have been added are stoppered with a gas collection apparatus and left sitting at room temperature until all flasks have been completed. Six ml samples are withdrawn from all control flasks as the 0 time samples. The incubation period and the collection of gas evolved during fermentation is initiated 10 minutes after the flasks have been placed in a 38°C water bath. Flasks are incubated with shaking (90 oscillations per minute) for 4 hours.

The volume of gas produced by each fermentation is measured at 1/2 hour intervals. The manometric apparatus for collection of gas and measurement of the volume evolved has been described by Trei et al., J. Anim.

Sci., 30, 825 (1970).

Rumen fluid is poured into 25 x 150 mm glase tubes and left in an ice bath for approximately 15 minutes to permit settling of particulate matter. The 6 ml quantity of rumen fluid is then added to a 2 ml quantity of 25 o/o (W/V) metaphosphoric acid in 13 ml polycarbonate centrifuge tubes. Each tube is stoppered and thoroughly mixed. The Tubes are left in an ice bath for 30 minutes and then centrifuged at 16,000 rpms for 10 minutes. A 1 ml quantity of the internal standard (0.25 o/o 2-methyl valeric acid) is then added to a 4 ml quantity of the supernate. The resulting mixture is filtered through a 0.22 micron Millipore filter using a 5 ml syringe. The filtrate is sealed in one ml glass vials with Teflon lined 489 99 - 24 rubber crimp septa.

Each vial, representing each of the individual fer mentations, is analyzed for volatile fatty acids.

The results are stated in the following table: - 25 co Μ ηΊ β ΕΗ Ο •Η Ρ d Ρ β φ a β φ <Η β φ β •Η β ο •Η Ρ ϋ d Ο β Α <1 Ρη d β d ω d Μ β ο ω φ β ο χ! β σ β ο Ή ω 3 Ο α» β d rH γ—( Φ ϋ ω <Η Ρ Μ ratio of C.,: (C„ + G.) is normalised to a value of 10Q for the untreated control - 48999 - 25 2 Conpounds of formula I wherein R is aryl, haloaryl or nitroaryl and their pharmaceutically acceptable salts are orally active as antimalarial agents. This acitivity is demonstrated by the following activities against the malaria causing agent Plasmodium berghei in mice: Compound ED^mg/kg p.o Monensin A, 4-ehlorophenylurethane 2.3 Monensin A, phenylurethane 4 Monensin A, 4-bromophenylurethane 15-20 Compounds of formula I and their pharmaceutically acceptable salts are orally active as antihypertensive agents. This activity is demonstrated by the following table (Table 9): - 27 tab: X> CO fc Φ «Η Φ fc A Φ fc erf Φ •P erf fc -p fc erf Φ xi •p o fl fl ^2 u> fc fl CQ CQ Φ fc A Ά O O «Η Φ -fl ϋ «Η Χί £ CO Ά fl fl Ο A fl Ο 8 9 9 9 - 28 The compound of the present invention can be prepared by reacting monensin A or B, viz. a compound of the general formula OH II wherein R is methyl (monensin B) or ethyl (monensin A) or a salt thereof with an isocyanate of the formula R^-NCO XII wherein R1 is as above Preferably a salt of the starting compound of formu· la II is used, in particular the sodium salt. The isocyanate of formula III is preferably added in slight excess, e.g., about 10 o/o excess, so as to optimize the formation of mono derivative. The reaction is preferably carried out in an inert solvent such as a chlorinated hydrocarbon, e.g. carbon tetrachloride, methylene chloride or chloroform, ether, ethyl acetate or in an aromatic hydrocarbon solvent such as benzene or toluene. The reaction temperature is not critical but can be between 2o about 0°C and the boiling point of the reaction mixture, preferably at about room temperature.

Example 1 Shake flask fermentation of Streptomyces X—14667 The X—14667 culture is grown and maintained on a starch agar slant having the following composition (grams /liter distilled water): Starch N-Z amine A Beef extract Yeast extract CoC12.6H20 Agar .0 2.0 1.0 1.0 0.02 .0 The slant is inoculated with X-14667 culture and incubated at 28°C for 7—14 days. A chunk of agar containing the sporulated culture from the agar slant is then used to inoculate a 500-ml Erlenmeyer flask containing 100 ral sterilized inoculum medium having the following composition (grams/liter distilled water): Tomato pomace 5.0 Distillers soluble 5.0 Peptone 5.0 Debittered yeast 5.0 Corn starch 20.0 CaCOg 1.0 1.0 Adjust pH to 7-0 with NaOH before sterilization.

The inoculated inoculum medium is incubated at 28°C for 48—72 hours on a rotary shaker operating at 250 rpm with a 2-ineh stroke. 9 9 9 - 30 A 3 ml portion (3 o/o, v/v) of the resulting culture is then used to inoculate a 500-ml Erlenmeyer flask containing 100 ml sterilized production medium having the following composition (grams/liter distilled water): Tomato pomace Distillers soluble Peptone Debittered yeast Corn starch CaCO3 κ2ηρο4 pH is adjusted to 7· .0 .0 .0 .0 .0 1.0 1.0 with NaOH before autoclaving.

The inoculated medium is incubated at 28°C for 5 days on a rotary shaker running at 250 rpm with a 2-inch stroke.

Example 2 Tank fermentation of Streptomyces X-14667 The X-14667 culture is grown and maintained on a starch casein agar slant having the following composi20 tion (grams/liter distilled water): Soluble starch 10.0 Casein 1.0 k2hpo4 0.5 MgSO^ianhydrous) 0.5 Agar 20.0 The slant is inoculated with X-14667 culture and incubated at 28°C for 7-10 days. A chunk of agar from Adjust to pH 7.4 with NaOH before autoclaving. the sporulated culture is then used to prepare vegetative inoculum by inoculating a 500-ml Erlenmeyer flask containing 100 mis of inoculum medium having the following composition (grams/liter distilled water): Tomato pomace Distillers soluble Peptone Debittered yeast Corn starch CaCOg k2hpo4 .0 .0 .0 .0 .0 1.0 1.0 pH is adjusted to 7.0 before autoclaving.

The inoculated medium is incubated for 96 hours at 28°C on a rotary shaker operating at 250 rpm, 2-inch stroke.

Twenty ml (1 o/o, v/v) of this culture are used to inoculate a 6-liter Erlenmeyer flask containing 2 liters of medium having the following composition (grams/liter distilled water): Tomato pomace 5.0 Distillers soluble 5.0 Peptone 5.0 Debittered yeast 5.0 Corn starch 20.0 CaCOg 1.0 1.0 pH is adjusted to 7.0 before autoclaving at 15-20 pound pressure for 45 minutes.

The inoculated medium is incubated for 72 hours at 28°C on a rotary shaker operating at 250 rpm. - 32 Six liters of this culture are used to inoculate 230 I of the following medium in a 380 1 fermentor (grams,' liter tap water): Tomato pomace Distillers soluble Peptone Debittered yeast Corn starch CaCO^ k2hpo4 Antifoam .0 .0 .0 .0 .0 1.0 1.0 0.1 The pH of the medium is adjusted to 7.0 with NaOH 2 before sterilization for 1 1/4 hours with 4 kg/cm steam.

The inoculated medium is aerated with compressed 15 air at a rate of 9 1 per minute and is stirred with agitators at 280 rpm. The fermentation is carried out at 28°C for 5 days.

Example 3 Isolation of Monensin A, Monensin B and diphenethylurea The whole broth from a 230 1 fermentation of Streptomyces sp. X-14667 was extracted at pH 7.6 with an equal volume of ethyl acetate. The solvent layer was separated and concentrated under reduced pressure to 1.0 liter.

The solvent concentrate was washed sequentually with equal volumes of 1 N HCl, water, saturated sodium carbonate, and water and then was dried over sodium sulfate. Further concentration and filtration gave a crystalline mixture containing Monensin A, Monensin B and diphenethylurea and an oil.

Example 4 Isolation of Monensin A and diphenethylurea The mixed crystals obtained as per Example 3 were dissolved in 100 ml of methylene chloride and washed with IN HCl. The solvent layer was concentrated to a small volume and on addition of n-hexane diphenethylurea (mp 136°C) was separated by filtration.

The filtrate (mother liquor) was diluted with diethylether, washed with saturated sodium carbonate, and upon concentration and addition of n-hexane crystalline monensin B (mp 276°C) was separated, and a second crop of crystals was also recovered.

By repeated thin layer chromatography on silica gel (development solvent ethylacetate) it was determined that the second crop of crystals was a mixture of monensin B and monensin A.

Example 5 Isolation of Monensin A phenethylurethane and Monensin B phenethylurethane The oil from the first filtration (Example 3) was dissolved in n-hexane (0.47 liters) and extracted twice with 0.47 liters of acetonitrile. The extracts were pooled, concentrated to an oil, and washed with n-hexane.

The n-hexane insoluble, oily solid was dissolved in diethyl ether, filtered and chromatographed on 500 grams of silica gel eluting with a gradient between 5 liters methylene chloride to 5 liters of methylene chloride-ethanol (9:1)· Fractions of about 18 ml each were collected and nos. 120 to 180 were pooled for rechromatography. Fractions nos. 185 to 235 were pooled, concentrated under reduced » 48933 - 34 pressure to an oily solid, dissolved in diethyl ether and washed successively with IN HCl, saturated sodium carbonate and water. The solvent was evaporated under reduced pressure to give raonensin B phenethylurethane, sodium salt as a powder, mp 70°C; [a]p +48° (CHCl^, C=1 o/o), +44° (CHgOH, C =1 o/o). Elementary analysis: Calc.: c44H68N012Na (826.98): C, 63.90; H, 8.41; N, 1.69; Na, 2.78. Found: C, 64.45; H, 8.68; N, 1.76; Na, 2.31.

Two hundred mg of the sodium salt was dissolved in ethylacetate and washed with IN HCl. The solvent was evaporated under reduced pressure yielding 100 mg of monensin B phenethylurethane as a beige powder, mp 50°C [a]p +59.6° (CHClg, C=1 o/o); +45.8° (CH^OH, C=1 o/o). Elementary analysis: Calc.: C^HggNO^ (804-.4): C, 65.65; H, 8.76; N, 1.74; 0, 23-85. Found: C, 65.53; H, 8.16; N, 1.49; 0, 24.16.

The pooled fractions nos. 120 to 180 were concentrated under reduced pressure to an oil and rechromatographed on a 700 g. silica gel column. The column was eluted initially with 4 liters of ethyl acetate, then 4 liters of ethyl acetate-acetone (1:1) and finally 4 liters of ethyl acetate-ethanol (95:1). The fractions nos. 29 to 35 (pooled) upon concentration yielded diphenethylurea. The pooled fractions nos. 86 to 121 upon con25 centration yielded 2 grams of Monensin B phenethylurethane. The pooled fractions nos. 55 to 85 were concentrated under reduced pressure to an oily solid and rechromatographed using n-hexane-acetone (8:2). The two component mixture was resolved to give Monensin B phenethyluretha30 ne and Monensin A 2-phenethylurethane^ the latter as a powder upon concentration, mp 103°C [a]p+50° (CHCl^, C=1 o/o) Calc.: C^H^NO^Na (840.04); C, 64.34; H, 8.40; N, 1.67; Na, 2.73. Found: C, 64.43; H, 8.29; N, 1.92; Na, 2.49. - 35 48993 These structures of the end products were confirmed by synthesis from Monensln A and B respectively. The semi-synthetic material was prepared in both cases by dissolving 1 mmole of the antibiotic in benzene and adding 1.2 mmole of phenethyl isocyanate. After reacting overnight, the compounds were worked up by washing the reaction mixture with aqueous Na2C0g and evaporating the solvent under reduced pressure. The crude reaction products were purified by silica gel chromatography as described for the fermentation end products. The semi-synthetic and fermentation products were shown to be identical by mp., [a]D, IR, NMR and MS.

The phenethyl isocyanate used in the above reaction can be prepared as follows: grams of phenethyl amine in 300 ml of dry toluene saturated with dry HCl gas was mixed until a heavy white precipitate formed. An additional 200 ml of dry toluene was added with 50 ml of phosgene (12.5 o/o in benzene).

The mixture was refluxed (10 min.) and then 450 ml of phosgene was slowly added over 30 minutes and the mixture refluxed for 4 hours. The reaction mixture was allowed to cool to room temperature slowly and the solvent removed in vacuo leaving a yellow oil. Vacuum distillation of the oil at 82° to 83°C/0.1 mm yielded 1.8 g of end product.

Example 6 Preparation of the 4-bromophenylurethane of monensin A from monensin A free acid Ten millimoles (6.89 g) of monensin A hydrate was dissolved in benzene (100 ml. )^ and to this solution an excess (11 mmole) of 4-bromophenyl isocyanate in an equal volume of benzene was added and the reaction mixture stirred at - 36 489 99 room temperature. The course of the reaction was followed by silica gel TLC using ethyl acetate-n-hexane-ethanol (80:20:2) as development solvent and vanillin-phosphoric acid reagent for detection.

After one week, the reaction appeared complete and the reaction mixture was washed in turn with 0.5 N HC1, water, saturated Na2C0g and water. The benzene solution was dried (Na-jSOjj) and evaporated under reduced pressure to an amorphous solid. The derivative was crystallized from acetonitrile to yield the sodium salt of 4-bromophenylurethane of monensin A, mp 201 to 203° C, [alD +65.3° (CHClg, C=1 o/o). Calcd. for C43 HggO12NBrMa (891.87), o/o C, 57.90; H, 7.46; N, 1.57; Br, 8.96. Found o/oC, 58.57; H, 7-36; N, 1.23; Br, 8.90.

Example 7 Preparation of 4-bromophenylurethane of monensin A from the sodium salt of monensin Starting with 5 g. of the monensin A sodium salt (7 mmole) and 2 g. of 4-bromophenyl isocyanate, the reae2o tion was run as in Example 6, but the sodium salt appeared to react faster, and by TLC the reaction was complete after two days.

After work-up as before, there was produced 4-bromophenylurethane of monensin A. - 37 Example 8 Following the teachings of Examples 6 and 7, there may be produced by utilizing the appropriate isocyanate the following compounds: Compound melting point °C optical rotations Λ θ Monensin A, methylurethane 191-193 Monensin A, 4-hromophenethyl- urethane 201-203 Monensin B, (R)-l-phenyle thylurethane 89-93 Monensin A, phenylurethane 199-210 Monensin A, 4-chlorophenyl- u?'thane 199-207 Monensin B, (S)-1-phenyl- ethylurethane 116-120 Monensin A, cyclohexyl- urethane 110-123 Monensin A, 2-(phenyl)-cyclo- propyl urethane 119-124 Monensin A, 4-fluorophenyl- urethane 199-223 Monensin A, 4-nitrophenyl- urethane 189-192 + 104.7(1%,CHjCN) Monensin A, 4-methylphenyl- urethane 220 + 59.6(1%,CHClj) Monensin A, 4-iodophenylurethane 203-206 + 67.6(1%,CHC15) Monensin A, n-butylurethane + 59.2(1%,CHC13) Monensin A, 4-phenoxyphenyl- urethane 210-213 + 67.9(1%,CHC13) Example 9 TABLET FORMULATIONS: (Wet Granulation) Item Ingredients mg/tablet mg/tablet mg/tablet 1. Monensin B phenethylurethane or Monensin A phenethylurethane 15 30 60 2. Lactose 188 173 188 3. Modified Starch 25 25 30 4. Pregelatinized Starch 20 20 20 5. Distilled water q.s. - - - 6. Magnesium stearate _2 _2 _2 Weight of tablet 250 mg 250 mg 300 mg PROCEDURE: 1) Mix Items 1-4 in a suitable mixer. 2) Granulate with sufficient distilled water to proper consistency. Mill. 3) Dry in a suitable oven. 4) Mill and mix with magnesium stearate.

) Compress on a suitable press for 3 minutes equipped with appropriate punches. - 39 Example 10 TABLET FORMULATIONS: (Direct Compression) Item Ingredients mg/tablet mg/tablet mg/tablet 1. Monensin B phen- 15 30 60 5 ethylurethane or Monensin A phenethylurethane 2. Lactose 207 192 162 3. Avicel 45 45 45 10 4. Direct Compression Starch 30 30 30 5. Magnesium Stearate 3 3 3 Weight of tablet 300 mg 300 mg 300 mg PROCEDURE: 15 1) Mix Item 1 with equal amount of lactose. Mix well. 2) Mix with Item 3, 4, and remaining amount of Item 2. Mix well. 3) Add magnesium stearate and mix for 3 minutes. 4) ' Compress on a suitable punch. - 40 Example 11 CAPSULE FORMULATIONS: Item Ingredients mg/capsule mg/capsule mg/capsule 1 . Monensin B phen- ethylurethane or Monensin A phen- ethylurethane 15 30 60 2. Lactose 239 224 194 3- Starch 30 30 30 10 4. Tale 15 15 15 5. Magnesium Stearate _χ _1_ _1_ Capsule fill weight 300 mg 300 mg 300 mg PROCEDURE: 1) Mix items 1-3 in a suitable mixer. 15 2) Add talc and magnesium stearate and mix for a short period of time. 3) Encapsulate on an appropriate encapsulation machine - 41 10 An animal feed Example 12 for use according to the invention: As Is, Dry Matter o/o by weight Basis o/o by weight Corn Silage 21.6 10.7 Dry Rolled Corn 70.7 80.0 Protein Supplement 7.7 9.3 Protein Supplement Alfalfa Hay, 15.49 Dry Rolled Sorghum Grain 3.72 Cottonseed Meal 63-56 Limestone 8.97 Salt (NaCl) 3.40 Trace Minerals 0.11 Vitamin A Premix 0.13 KC1 4.36 Monensin A phenethylurethane Premix (15 o/o by weight) 0.26 100.00 Monensin A phenethylurethane Premix Monensin A phenethylurethane Rice Hulls

Claims

1. CLAIMS:1. Urethane derivatives of the general formula wherein R 1 is phenyl, C^_ 7 ~alky1-phenyl, halogen-phenyl, 5 nitro-phenyl, phenoxy-phenyl, C^_ 7 -alkyl, cycloalkyl, pheny1-C 1 _ 7 ~alkyl, C 1 _ 7 ~alkanoy1-phenyl, C 1 _ 7 -alkoxy-phenyl or pheny1-C 3 _ 7 ~cycloalkyl and R 2 is methyl or ethyl, and their pharmaceutically acceptable salts. 10

2. A compound according to claim 1, wherein R^ is phenyl, C 3 _ 7 ~alky1-phenyl, halogen-phenyl, nitro-phenyl, C 3 _ 7 -alkoxy-phenyl, phenoxy-phenyl, C^_ 7 ~alkanoy1-phenyl or C 3 _ 7 ~cycloalkyl.

3. A compound according to claim 1, wherein R^ is 15 phenyl, C^^-alky 1-phenyl or halogen-phenyl.

4. A compound of any one of claims 1-3, wherein R is ethyl.

5. A compound of any one of claims 1-4, wherein R 1 is phenyl or halophenyl. 20

6. A compound of claim 5, wherein is phenyl and R is ethyl.

7. A compound of claim 5, wherein is 4-chloro48999 - 43 ρ phenyl and R is ethyl.

8. A compound of claim 5, wherein R 1 is 4-bromophenyl 2 and R is ethyl.

9. A compound of claim 5, wherein R 1 is fluoro2 5 phenyl and R is ethyl.

10. A compound of claim 5, wherein R 1 is 4-nitro2 phenyl and R is ethyl.

11. A compound of claim 1 or 4 wherein R 1 is phenethyl . - 44 48999

12. Compounds as set forth in any one of claims 111 as pharmaceutically active substances.

13. Compounds as set forth in any one of claims 111 as pharmaceutically active substances for the treat5 ment and prophylaxis of bacterial diseases, ooccidiosis, hypertension, malaria and/or swine dysentery.

14. Compounds as set forth in any one of claims 111 for use in increasing the efficiency of feed utilisation in ruminants and monogastric animals which ferment fibrous vegetable matter in the cecum. - 45 15. A process for the manufacture of the urethane derivatives set forth in any one of claims 1-11, which comprises reacting a compound of the formula 5 wherein R is methyl or ethyl with an isocyanate of the formula

15.R'-NCO III wherein R 1 is as in claim 1.

16. Process according to claim 15, wherein the iso10 cyanate of formula III is added In slight, e.g. about 10 o/o excess.

17. Process for the manufacture of the compounds set forth in claim 11, i.e. where R 1 is phenethyl, which comprises cultivating a subculture of one of the strains

18. Streptomyoes sp. X-14667 NRRL 11336 (ATCC 31551), Streptomyces sp. X-14573 NRRL 11337 (ATCC 31552) and Streptomyoes sp. X-14575 NRRL 11338 (ATCC 31553) in an aqueous carbohydrate solution containing a nitrogenous nutrient under submerged aerobic conditions and thereafter isolating 20 the end product from said solution. - 46 18. A pharmaceutical preparation containing a compound as set forth in any one of claims 1-11.

19. A pharmaceutical preparation for the treatment and prophylaxis of bacterial diseases, coccidiosis, hy5 pertension, malaria and/or swine dysentery containing a compound as set forth in any one of claims 1-11.

20. A premix or a composition for ready consumption increasing the effioiency of feed utilisation in ruminants and monogastrio animals which ferment fibrous veto getable matter in the cecum containing a compound as set forth in any one of claims 1-11.

21. Compounds as claimed in claim 1, whenever prepared according to the process claimed in claim 15 or 16. Or by an obvious chemical equivalent thereof.

22. Compounds as claimed in claim 11, whenever prepared according to the process in claim 17 or by an obvious equivalent thereof.