IL96280A - Process for the preparation of aminotriazine derivatives - Google Patents

Process for the preparation of aminotriazine derivatives

Info

Publication number
IL96280A
IL96280A IL9628090A IL9628090A IL96280A IL 96280 A IL96280 A IL 96280A IL 9628090 A IL9628090 A IL 9628090A IL 9628090 A IL9628090 A IL 9628090A IL 96280 A IL96280 A IL 96280A
Authority
IL
Israel
Prior art keywords
phenyl
formula
compound
methyl
substituted
Prior art date
Application number
IL9628090A
Other languages
Hebrew (he)
Other versions
IL96280A0 (en
Original Assignee
Ciba Geigy Ag
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ciba Geigy Ag filed Critical Ciba Geigy Ag
Priority to IL11161790A priority Critical patent/IL111617A/en
Publication of IL96280A0 publication Critical patent/IL96280A0/en
Priority to IL11161794A priority patent/IL111617A0/en
Publication of IL96280A publication Critical patent/IL96280A/en

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D253/00—Heterocyclic compounds containing six-membered rings having three nitrogen atoms as the only ring hetero atoms, not provided for by group C07D251/00
    • C07D253/02—Heterocyclic compounds containing six-membered rings having three nitrogen atoms as the only ring hetero atoms, not provided for by group C07D251/00 not condensed with other rings
    • C07D253/06—1,2,4-Triazines
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D271/00—Heterocyclic compounds containing five-membered rings having two nitrogen atoms and one oxygen atom as the only ring hetero atoms
    • C07D271/02—Heterocyclic compounds containing five-membered rings having two nitrogen atoms and one oxygen atom as the only ring hetero atoms not condensed with other rings
    • C07D271/10—1,3,4-Oxadiazoles; Hydrogenated 1,3,4-oxadiazoles
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D271/00—Heterocyclic compounds containing five-membered rings having two nitrogen atoms and one oxygen atom as the only ring hetero atoms
    • C07D271/02—Heterocyclic compounds containing five-membered rings having two nitrogen atoms and one oxygen atom as the only ring hetero atoms not condensed with other rings
    • C07D271/10—1,3,4-Oxadiazoles; Hydrogenated 1,3,4-oxadiazoles
    • C07D271/113—1,3,4-Oxadiazoles; Hydrogenated 1,3,4-oxadiazoles with oxygen, sulfur or nitrogen atoms, directly attached to ring carbon atoms, the nitrogen atoms not forming part of a nitro radical
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D401/00—Heterocyclic compounds containing two or more hetero rings, having nitrogen atoms as the only ring hetero atoms, at least one ring being a six-membered ring with only one nitrogen atom
    • C07D401/02—Heterocyclic compounds containing two or more hetero rings, having nitrogen atoms as the only ring hetero atoms, at least one ring being a six-membered ring with only one nitrogen atom containing two hetero rings
    • C07D401/12—Heterocyclic compounds containing two or more hetero rings, having nitrogen atoms as the only ring hetero atoms, at least one ring being a six-membered ring with only one nitrogen atom containing two hetero rings linked by a chain containing hetero atoms as chain links
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D413/00—Heterocyclic compounds containing two or more hetero rings, at least one ring having nitrogen and oxygen atoms as the only ring hetero atoms
    • C07D413/02—Heterocyclic compounds containing two or more hetero rings, at least one ring having nitrogen and oxygen atoms as the only ring hetero atoms containing two hetero rings
    • C07D413/06—Heterocyclic compounds containing two or more hetero rings, at least one ring having nitrogen and oxygen atoms as the only ring hetero atoms containing two hetero rings linked by a carbon chain containing only aliphatic carbon atoms

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Plural Heterocyclic Compounds (AREA)
  • Heterocyclic Carbon Compounds Containing A Hetero Ring Having Nitrogen And Oxygen As The Only Ring Hetero Atoms (AREA)
  • Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
  • Nitrogen And Oxygen Or Sulfur-Condensed Heterocyclic Ring Systems (AREA)
  • Agricultural Chemicals And Associated Chemicals (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Description

REF 1671 /90 PROCESS FOR THE PREPARATION OF AMINOTRIAZINE DERIVATIVES 96280/2 Process for the preparation of aminotriazine derivatives The present invention relates to a novel process for the preparation of 4-armno-3-oxo-2,3,4,5-tetrahydro-l,2,4-triazines.
The invention relates to a process for the preparation of a compound of formula I wherein R is hydrogen, C1-C6alkyl, C3-C6cycloalkyl, Cj^alkyl substituted by from 1 to 9 halogen atoms or by from 1 to 3 radicals from the group C^^alkoxy, Ci^alkylthio and phenyl, phenyl or phenyl substituted by from 1 to 3 radicals from the group halogen, methyl, ethyl, methoxy, methylthio and nitro, which process comprises reacting with hydrazine hydrate a compound of formula Π wherein Rj is hydrogen, C1-C4alkyl, C3-C6cycloalkyl, Q^alkyl substituted by from 1 to 9 chlorine atoms, CrC3alkoxy, C1-C3alkylthio, C1-C3alkylsulfinyl, CrC3alkylsulfonyl, phenyl, phenyl substituted by from 1 to 3 radicals from the group halogen, methyl, ethyl, methoxy, methylthio and nitro, or pyridyl, and R is as defined above; and subjecting the resulting compound of formula ΠΙ H to hydrolysis, preferably acid hydrolysis.
The present process is preferably used for the preparation of compounds of formula I wherein R is methyl, ethyl, isopropyl, tert.-butyl or cyclopropyl. The process is preferably carried out using compounds of formula Π wherein Rj is CrC4alkyl as starting materials.
The aminotriazine derivatives of formula I prepared according to the invention can be used as intermediates for the preparation of 4-[(pyrid-3-yl)-methyleneamino]- or 4-[(pyrid-3-yl)-methylanuno]-3-oxo-2,3,4,5-tetrahydro-l,2,4-triazines, which are distinguished by pronounced insecticidal and acaricidal activity. Such pesticidal compounds are, for example, 4-[(pyrid-3-yl)-methyleneamino]-3-oxo-6-methyl-2,3,4,5-tetrahydro- 1,2,4-triazine, 4-[(pyrid-3-yl)-methyleneamino]-3-oxo-6-cyclopropyl-2,3,4,5-tetrahydro- 1 ,2,4-triazine, 4-[(pyrid-3-yl)-methylamino]-3-oxo-6-isopropyl-2,3,4,5-tetra-hydro- 1,2,4-triazine and 4-[(pyrid-3-yI)-methylamino]-3-oxo-6-tert.-butyl-2,3,4,5-tetra-hydro- 1,2,4-triazine. Such pesticidal compounds, their preparation and use are described in EP Patent Application 314,615 , corresponding to IL 87988.
The process according to the invention can be illustrated by the following reaction scheme, the radicals R and Rj being as defined above: (Π) 96280/2 - 3 - H H (ΠΙ) (I) The first step (ring expansion) of the process according to the invention for the preparation of the compounds of formula I is usually carried out under normal pressure and preferably in a solvent. The temperature is from +15 to 120°C, preferably from +20 to 100°C.
Suitable solvents are, for example, water, nitriles, such as acetonitrile, alcohols, dioxane or tetrahydrofuran. The subsequent hydrolysis of the acylamino compounds of formula ΙΠ to form the free amino compounds of formula I is preferably carried out with inorganic acids, such as IN hydrochloric acid to cone, hydrochloric acid or IN to ION sulfuric acid, at temperatures of from 0 to 120°C, especially from +20 to 100°C, in an aqueous medium or in organic solvents, such as alcohols, dioxane, tetrahydrofuran, nitriles, etc..
The l,3,4-oxadiazolin-2-one-3-yl-ketones of formula II used as starting materials according to the invention are novel. They can be prepared analogously to known procedures, for example as follows (see, for example, EP Patent Application no. 314,615): In the above formulae IV and V, R and Κ are as defined above and X is a halogen atom, preferably chlorine or bromine. The above process for the preparation of the oxadiazolone ketones of formula Π is generally carried out under normal pressure in the presence of a base and in a solvent. The temperature is from 0 to +150°C, preferably from +20 to 100°C. Suitable bases are organic and inorganic bases, for example trimethylamine, alcoholates, sodium hydroxide or sodium hydride. Suitable solvents are, inter alia, alcohols, halogenated hydrocarbons, for example chloroform, nitriles, for example acetonitrile, tetrahydrofuran, dioxane, dimethyl sulfoxide, dimethylformamide or water. 96280/3 - 4 - The oxadiazolones of formula IV [see EP Patent Application No. 321 ,833; J. Pharm. Soc. Japan 76, 1300-1303 (1956); B. 82, 121-123 ( 1949)1 and their preparation, and also the haloketones of formula V, are for the most part known.
It is known from Liebigs Ann. Chem. 749, 125 ff. (1971) that 4-amino-6-phenyl-3-oxo-2,3,4,5-tetrahydro-l,2,4-triazines can be obtained starting from 2-amino-5-methyl-3-phenacyl- l,3,4-oxadiazolium bromide by reaction with hydrazine hydrate. The main disadvantage of this process is that it is limited to the preparation of 1,2,4-triazine rings that are phenyl-substituted in the 6-position; in addition, this process comprises several steps and its yield is poor. Furthermore, it is known from EP Patent Application No. 314,615 to prepare 4-amino-3-oxo-2,3,4,5-tetrahydro-l,2,4-triazines that are substituted in the 6-position, by reacting corresponding 5-trifluoromethyl-l,3,4-oxadiazolin-2-one-3-yl ketones with excess hydrazine in a one-step reaction: (na) H (la) wherein A may be an unsubstituted or substituted alkyl or aryl substituent. The disadvantages of this process are primarily the high cost of the trifluoroacetic acid ethyl ester required for preparing the trifluoroacethydrazide, the instability of that trifluoroacet-hydrazide at room temperature, and the not very high yield in the reaction of the trifluoroacethydrazide with phosgene in water (see Helv. Chim. Acta 1986, 333) to prepare the 5-trifluoromethyl-l,3,4-oxadiazolin-2(3H)-one from which the 5 -trifluorom ethyl- 1,3,4-oxadiazolin-2-one-3-yl-ketones of formula Ila above (starting compound) are obtained. Moreover, the reaction according to EP Patent Application No. 314,615 inevitably produces toxic trifluoroacetic acid derivatives as a by-product, which present ecological problems and require a considerable outlay for their disposal.
In contrast, within the scope of the present invention it has now surprisingly been found that the presence of a 5-CF3 group in the starting compounds of formula II is not necessary for the preparation of the 4-arnino-3-oxo-2,3,4,5-tetrahydro-l,2,4-triazines of formula I by 96280/3 -5- ring expansion. The present starting compounds of formula Π, which contain one of the mentioned radicals K\ in the 5-position instead of the mentioned CF3 group, react readily with hydrazine hydrate to form the acylamino compounds of formula III, from which, however, the radical -CO-Ri must subsequently be removed by acid hydrolysis to obtain the compounds of formula I. With the process according to the invention, the disadvantages of the procedures hitherto available are eliminated since, in the process according to the invention, inexpensive and readily available starting compounds can be used, high yields are obtained and, instead of toxic trifluoroacetic acid derivatives, ecologically harmless carboxylic acid derivatives, for example acetic acid, are formed as a by-product.
Subject matter described but not claimed is given as background information.
Example 1 : Preparation of the starting compound 2.3 -Dihydro-5 -methyl- 1.3.4-oxadiazolin-2-one-3 -yl-acetone 10 g of 2,3-dihydro-5-methyl-l,3,4-oxadiazolin-2-one (prepared in customary manner from acethydrazide and phosgene) are added to a solution of 2.3 g of sodium in 100 ml of methanol, the mixture is stirred for a short time and then the solvent is removed in vacuo at a bath temperature of 60°C. The sodium salt so formed is introduced in portions into a solution of 9.2 g of chloroacetone and 0.2 g of tetrabutylammonium bromide in 50 ml of chloroform, and the reaction mixture is stirred for 4 hours at 65°C. After the salts have been filtered off, the solvent is removed in vacuo at a bath temperature of 50°C. The residue that remains is recrystallised from tert. -butyl methyl ether, yielding the title compound having a melting point of 55-57°C.
The following compounds of formula Π are also prepared in a manner corresponding to that described above: R R phys. data H -CH3 b.p. 0.08 torr/80°C -CH3 -CH3 m.p. 55-58°C -C(CH3)3 -CH3 b.p. 0.07 torr/102°C -CH3 -CC13 96280/2 - 7 - Example 2: a) Preparation of 4-acetylamino-6-methyl-3-oxo-2,3,4,5-tetrahydro-l,2,4-triazine (ring expansion): 3.12 g of 2,3-dihydro-5-methyl-l,3,4-oxadiazolin-2-one-3-yl-acetone prepared according to Example 1 are stirred in 40 ml of alcohol together with 2 g of hydrazine hydrate for 16 hours at a bath temperature of 35°C. After the solvent and the excess hydrazine have been evaporated off in vacuo, recrystallisarion from isopropanol yields the title compound having a melting point of 197-199°C.
The following compounds of formula ΙΠ are also prepared in a manner corresponding to that described above: Ri R m.p. [°C] H -CH3 185-187° -CH3 -CH3 197-199° -C(CH3)3 -CH3 205-207° -CH3 H -CH3 -CF3 H H b) Preparation of 4-arnino-6-rnethyl-3-oxo-2,3,4,5-tetrahvdro-l,2,4-rriazine (acid hydrolysis): 1.7 g of the 4-acetylamino-6-methyl-3-oxo-2,3,4,5-tetrahydro-l,2,4-triazine prepared according to a) above are stirred for 5 hours in 10 ml of 2N hydrochloric acid at 80°C. After cooling of the solution, 1.7 g of sodium acetate are added and the solution is concentrated by evaporation in a rotary evaporator at a bath temperature of 60°C. The residue formed is stirred with ethanol and freed of salt precipitates by filtration. The resulting solution is concentrated to a small volume and caused to crystallise. The tide compound is obtained in the form of colourless crystals having a melting point of 116-119°C.
The following compounds of formula I are also prepared in a manner corresponding to that described above: R m.p. [°C] -CH3 116-119° -C2H5 143-145° -C3H7(i) 79- 81° -C(CH3)3 148-150° - 94- 95° H -CF3

Claims (6)

96280/2 - 10 - What is claimed is:
1. A process for the preparation of a compound of formula I wherein R is hydrogen, Cj-Cgalkyl, C3-C6cycloalkyl, C1-C4alkyl substituted by from 1 to 9 halogen atoms or by from 1 to 3 radicals from the group C Csalkoxy, and phenyl, phenyl or phenyl substituted by from 1 to 3 radicals from the group halogen, methyl, ethyl, methoxy, methylthio and nitro, which process comprises reacting with hydrazine hydrate a compound of formula Π wherein Rj is hydrogen, Ci-C4alkyl, C3-C6cycloalkyl, Ci-C4aU yl substituted by from 1 to 9 chlorine atoms, Cx-Csalkoxy, C^Csalkylthio, C1-C3alkylsulfinyl, C1-C3alkylsulfonyl, phenyl, phenyl substituted by from 1 to 3 radicals from the group halogen, methyl, ethyl, methoxy, methylthio and nitro, or pyridyl; and R is as defined above; and subjecting the resulting compound of formula ΙΠ to hydrolysis. 96280/2
2. A process according to claim 1, wherein the compound of formula III is subjected to acid hydrolysis.
3. A process according to claim 1 or 2, wherein the compound of formula III subjected to hydrolysis with an inorganic acid.
4. A process according to any one of claims 1 to 3 for the preparation of a compound of formula I wherein R is methyl, ethyl, isopropyl, tert.-butyl or cyclopropyl.
5. A process according to any one of claims 1 to 4, wherein a compound of formula II wherein Ri is C1-C4 alkyl is reacted.
6. A compound of formula wherein R is hydrogen, Ci-C6alkyl, C3-C6cycloalkyl, Ci-C4alkyl substituted by from 1 to 9 halogen atoms or by from 1 to 3 radicals from the group Ci-C3alkoxy, Ci-C3alkylthio and phenyl, phenyl or phenyl substituted by from 1 to 3 radicals from the group halogen, methyl, ethyl, methoxy, methylthio and nitro, and Ri is hydrogen, Ci-C4alkyl, C3-C6cycloalkyl, Ci-C4alkyl substituted by from 1 to 9 chlorine atoms, Ci-C3alkoxy, Ci-C3alkylthio, Ci-C3alkylsulfinyl, Ci-C3alkylsulfonyl, phenyl, phenyl substituted by from 1 to 3 radicals from the group halogen, methyl, ethyl, methoxy, methylthio and nitro, or pyridyl; with the proviso, that Rj is not methyl, n-butyl, benzyl or phenyl, when R is phenyl. L U ZZATTO & LUZZATTO
IL9628090A 1989-11-15 1990-11-08 Process for the preparation of aminotriazine derivatives IL96280A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
IL11161790A IL111617A (en) 1989-11-15 1990-11-08 Oxadiazolinones
IL11161794A IL111617A0 (en) 1989-11-15 1994-11-14 Oxadiazolinones

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CH410789 1989-11-15

Publications (2)

Publication Number Publication Date
IL96280A0 IL96280A0 (en) 1991-08-16
IL96280A true IL96280A (en) 1996-01-31

Family

ID=4269949

Family Applications (3)

Application Number Title Priority Date Filing Date
IL11161790A IL111617A (en) 1989-11-15 1990-11-08 Oxadiazolinones
IL9628090A IL96280A (en) 1989-11-15 1990-11-08 Process for the preparation of aminotriazine derivatives
IL11161794A IL111617A0 (en) 1989-11-15 1994-11-14 Oxadiazolinones

Family Applications Before (1)

Application Number Title Priority Date Filing Date
IL11161790A IL111617A (en) 1989-11-15 1990-11-08 Oxadiazolinones

Family Applications After (1)

Application Number Title Priority Date Filing Date
IL11161794A IL111617A0 (en) 1989-11-15 1994-11-14 Oxadiazolinones

Country Status (14)

Country Link
EP (1) EP0433218B1 (en)
JP (1) JP2943010B2 (en)
KR (1) KR0150208B1 (en)
CA (2) CA2320676C (en)
DE (1) DE59010496D1 (en)
DK (1) DK0433218T3 (en)
ES (1) ES2091815T3 (en)
GR (1) GR3020992T3 (en)
IE (1) IE73669B1 (en)
IL (3) IL111617A (en)
PT (1) PT95888B (en)
SG (1) SG43813A1 (en)
TW (1) TW199149B (en)
ZA (1) ZA909120B (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB9304178D0 (en) * 1993-03-02 1993-04-21 Ciba Geigy Ag Process for the preparation of 6-alkyl-4-(pyridin-3-yl-methyleneamino),5-dihydro-1,2,4-triazin-3(2h)-one
US5384403A (en) * 1993-03-31 1995-01-24 Ciba-Geigy Corporation Process for the preparation of aminotriazine derivatives

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5416515B1 (en) * 1968-08-19 1979-06-22
JPS6011478A (en) * 1983-06-30 1985-01-21 Showa Denko Kk Oxadiazolinon derivative and herbicide
US4699647A (en) * 1985-05-30 1987-10-13 E. I. Du Pont De Nemours And Company Herbicidal sulfonamides
DE3853662D1 (en) * 1987-10-16 1995-06-01 Ciba Geigy Ag Pesticides.

Also Published As

Publication number Publication date
JP2943010B2 (en) 1999-08-30
PT95888A (en) 1991-09-13
IE73669B1 (en) 1997-07-02
DE59010496D1 (en) 1996-10-17
IL111617A (en) 1996-05-14
GR3020992T3 (en) 1996-12-31
ES2091815T3 (en) 1996-11-16
DK0433218T3 (en) 1996-09-30
CA2320676C (en) 2004-11-02
EP0433218A1 (en) 1991-06-19
KR0150208B1 (en) 1998-10-15
CA2029838A1 (en) 1991-05-16
IL96280A0 (en) 1991-08-16
CA2029838C (en) 2001-06-19
IL111617A0 (en) 1995-01-24
ZA909120B (en) 1991-07-31
CA2320676A1 (en) 1991-05-16
EP0433218B1 (en) 1996-09-11
KR910009677A (en) 1991-06-28
TW199149B (en) 1993-02-01
PT95888B (en) 1997-11-28
SG43813A1 (en) 1997-11-14
IE904113A1 (en) 1991-05-22
JPH03188070A (en) 1991-08-16

Similar Documents

Publication Publication Date Title
JPH0317071A (en) Production of 3-amino-5-aminocarbonyl-1,2,4- triazoles derivatives
LU85442A1 (en) 1,2,4-TRIAZOL-3-ONE-BASED ANTIDEPRESSION AGENTS
JPH0714925B2 (en) Process for producing heteroaryloxyacetamide
NZ204964A (en) Heterocyclic-substituted 1,4-dihydropyridine derivatives and pharmaceutical compositions
US5648487A (en) Process for the preparation of aminotriazine derivatives
US3767667A (en) Process for preparing 1h-tetrazole compounds
US4824949A (en) Process for the preparation of pyrimidines
PL108034B1 (en) METHOD OF MAKING NEW TIAZOLO DERIVATIVES / 3,4-BMETHOD OF PRODUCING NEW DERIVATIVES OF THIAZOLO / 3,4-B / ISOQUINOLINE / IZOCHINOLINE
US5561230A (en) Process for the preparation of aminotriazine derivatives
KR100386312B1 (en) Process for the preparation of triazolidones and novel intermediates
IL96280A (en) Process for the preparation of aminotriazine derivatives
US9663490B2 (en) Process for making reverse transcriptase inhibitors
US4221798A (en) Hypotensive 2-heterocycloamino-imidazolines
JP3269192B2 (en) Method for producing 2-halogen-4,6-dialkoxy-pyrimidine
Cartwright et al. Gas-phase pyrolysis of 4-amino-3-allylthio-1, 2, 4-triazoles: a new route to [1, 3] thiazolo [3, 2-b][1, 2, 4] triazoles
HU212611B (en) Process for the preparation of 2-substituted 4,6-dialkoxy-pyrimidine derivatives
CA1044240A (en) Process for the preparation of 2-arylamino-2-imidazoline derivatives
US3746719A (en) 4-substituted 2-amino-1,3,4-thiadiazolones-(5) and process for their preparation
US5162534A (en) Process for the preparation of thiazoline derivatives
JPS6111954B2 (en)
GB2110668A (en) Imidazolecarboxamides
Collins et al. Dihydro-1, 2, 4-triazin-6 (1H)-ones. II Synthesis of Several Methylated 3-Phenyl-4, 5-dihydro-1, 2, 4-triazin-6 (1H)-ones
NO148556B (en) ANALOGUE PROCEDURE FOR THE PREPARATION OF PHARMACOLOGICALLY ACTIVE TRIAZINONES.
WO2000005233A1 (en) Method for preparing lintitript potassium salt
KR790001502B1 (en) Process for preparing benzo-2,4-thiazipines

Legal Events

Date Code Title Description
HK Corrigendum

Free format text: JOURNAL NO. 12/95 PAGE 3138, APPLICATION NO. 96280, THE CORRECT NUMBER OF THE PRIORITY DOCUMENT IS 4107/89-7

FF Patent granted
KB Patent renewed
KB Patent renewed
HP Change in proprietorship
KB Patent renewed
FF Patent granted
EXP Patent expired