baber/WOPTO huggingface dataset:
Patent HU-186018-B (HU)
Inventor: CSIKOS REZSOE
IPC: C07C67/00
Filed: 1982-05-12
Abstract: Die Erfindung betrifft ein Verfahren zur Herstellung des o-Phenylendiamins. Das o-Phenylendiamin wird aus Verbindungen der allgemeinen Formel (I), worin X für Wasserstoff oder Chlor steht, hergestellt, durch Reduktion mit Wasserstoff oder wasserstoffhaltigem Gas in der Anwesenheit von einem aktiven Hydrierkatalysator. Das Hydrieren wird in Anwesenheit von 30 bis 70 % Ammoniak und 10 bis 15 % Wasser zweckmäßig kontinuierlich durchgeführt, dann wird das Ammoniak aus der Lösung entfernt, der Katalysator abfiltriert, dann das Produkt durch Extraktion mit einem Lösungsmittel und/oder Kristallisieren abgetrennt. Formel.
Patent HU-187141-B (HU)
Inventor: BELI LASZLO
IPC: C07D213/26
Filed: 1982-06-30
Abstract: A találmány tárgya új eljárás 2,6-dimetil-piridinszármazékokat és szerves oldószereket tartalmazó ipari hulladékelegy környezeti ártalmasságának nagymértékű csökkentésére, és az elegy komplex feldolgozására oly módon, hogy a feldolgozandó 20-35 súly% kloroformot, 20-40 súly% metanolt, 10-15 súly% 2,6-bisz(hidroxi-metil)-piridint, 20-30 súly% 2,6-bisz(diklór-metil)-piridin és 2-(diklórmetil)-piridin keveréket tartalmazó hulladék elegyhez 10^-30 térf.% vizet adunk, az elegy pH-ját egy bázissal 8 és 10 közé állítjuk, a különvált vizesmetanolos felső vizes fázist elválasztjuk, a kloroformos alsó fázishoz 10-30 térf.% vizet adunk, az elegy pH-ját szükség esetén 8 és 10 közé állítjuk, a különvált vizes-metanolos felső vizes fázist elválasztjuk és az előző vizes-metanolos fázissal egyesítjük, majd a kloroformos alsó fázissal a vizes extrakciót még legalább kétszer megismételjük, ezután az összegyűjtött felső vizes-metanolos fázisokat kloroformmal mossuk, derítjük, kívánt esetben ásványi savval semlegesítjük, majd a matanolt és a víz egy részét elpárologtatjuk, és a párlatból a metanolt ismert módon regeneráljuk, a párlási maradékként kapott vizes oldatból a 2,6-bisz(hidroximetil)-piridint kristályosítjuk, majd a kívánt esetben szárítjuk és/vagy önmagában ismert módon tisztítjuk, a környezetre ártalmatlan sókat tartalmazó anyalúgját kiöntjük, a kloroformos alsó fázis! 15-20 térf.% mennyiségű tömény vizes sósavoldattal legalább kétszer extraháljuk, a fázisokat elválasztjuk, a kloroformos alsó fázisból a klorofornot desztillációval eltávolítjuk, a desztillációs maradékból kívánt esetben a 2,6-bisz(diklór-metil)pirídint elkülönítjük, míg a sósavas extraktumot, adott esetben hígítás után, egy bázissal semlegesítjük, a kivált olajat elkülönítjük és belőle kívánt eseiben a 2-(diklór-metil)-piridint kinyerjük, a viszszamaradó vizes nátrium-klorid-oldatot kiöntjük. A találmány előnye, hogy hulladékból értékes, kgzbenső termékként hasznosítható anyagok és újból felhasználható oldószerek visszanyerését teszi lehetővé a hulladék környezetre ártalmas megsemmisítése helyett. -1-
Patent HU-205009-B (HU)
Inventor: HEUER HUBERT
IPC: A61P11/08
Filed: 1989-05-05
Abstract: Bei der Anwendung von ß₂-Mimetika gemeinsam mit PAF-Antagonisten bei der Behandlung des Asthma bronchiale wird ein synergistischer Effekt erzielt.
Patent HU-197770-B (HU)
Title: Process for producing the new 9-square brackets open (2'r, 3'r, 4's)-3',4'-bis(hydroxymethyl)-2'-oxetanyl square brackets closed-hypoxanthine and pharmaceutical compositions comprising same as active ingredient
Inventor: SHIMADA NOBUYOSHI
IPC: C12P19/40
Filed: 1987-05-28
Abstract: The present invention relates to a novel compound having hypoxanthine base represented by the following formula: <CHEM> as well as to use of said compound and process for producing said compound. The novel compound of the present invention has an immunosuppressive and antiviral actions and is expected to be useful as a medical drug.
Patent HU-208444-B (HU)
Title: Apparatus for forming the internal wall of a construction for example channel being in the earth having profile particularly different from circle form
Inventor: MUELLER FRANZ PETER
IPC: B08B9/04
Filed: 1990-04-25
Abstract: In a machining device for working the inner wall of underground workings, for example of a channel, which deviates from a circular shape, with a motor driven tool, it is proposed for the sake of simply and quickly increasing, in an accurately profile-matched and low-vibration manner, the unobstructed cross-section of the underground workings to be repaired, that a frame (2) be provided which has a carrier (4), which runs essentially in the longitudinal direction of the profile (1) to be worked, and expansion feet (3), connected to said carrier, for fixing the position of the carrier in the underground workings, on which frame (2) a machining tool (12), for example a milling device, grinding disc or the like corresponding to the outline of the profile to be machined, can be movably held preferably along a connecting rod (6), the connecting rod (6) being similar to the profile to be machined and being located essentially perpendicular to the longitudinal axis of the channel (1) to be machined. <IMAGE>
Patent HU-187118-B (HU)
Title: Process for producing new thieno-thizaole derivatives
Inventor: SAUTER ROBERT
IPC: C07D513/14
Filed: 1983-08-17
Abstract: Compounds of the formula   <IMAGE>   wherein A is   <IMAGE>   and R is hydrogen, alkyl of 1 to 5 carbon atoms, alkanoyl of 1 to 5 carbon atoms, alkenyl of 3 to 5 carbon atoms, (alkoxy of 1 to 4 carbon atoms)carbonyl, or aralkyl of 7 to 11 carbon atoms optionally halo-substituted, and non-toxic, pharmacologically acceptable acid addition salts thereof. The compounds as well as their salts are useful as bradycardiacs.
Patent HU-198797-B (HU)
Inventor: BALANYI SZILVESZTER
IPC: G01R15/08
Filed: 1985-08-26
Abstract: A készülék berendezésorientált áramkört, ehhez
csatlakozó kiegészítő áramköröket, változtatható
ellenállásokat, diódákat és hangjelzőt
magában foglaló multiméteráramkört,
továbbá tápforrást, digitális kijelzőt, valamint
kezelőszervet tartalmaz.
A készülék lényege, hogy kezelőszerve
két, egy első és egy második nyomókapcsolóból
(12, 13) áll. Ezenkívül a készüléknek
egyes csatornákon (AV, B, C, D) át láncbakapcsolt
kétbemenetű vezérlóáramkóre (14),
számlálólánca (15), dekódoló áramköre (16),
miiltiméteráramköre (17) és digitális kijelzője
(18) van. A vezérlóáramkör (14) érintkezőire
a tápforrás (11), két bemenetére pedig az elsó
és a második nyomókapcsoló (12, 13) csatlakozik.
A digitális multiméter raérőbemenetét
pl. négy, egy első, egy második, egy harmadik
és egy negyedik csatlakozókapocs (A,íl,
K, U) képezi, melyek a multiniéteráramkör
(17) egyes mérőbemeneteire csatlakoznak. (1.
ábra)
Patent HU-197259-B (HU)
Title: Contact line for electric vehicles and method for producing same
Inventor: FORTIN PAUL-EMILE
IPC: B21B15/00
Filed: 1987-08-13
Abstract: A contact conductor for electric vehicles is produced from an aluminum alloy containing an excess of silicon. The alloy comprises 0.2-1% by weight magnesium, 1-7% by weight silicon and the balance being aluminum and inci­dental impurities. The conductor is produced by the steps of: (1) casting the alloy into a continuous bar, (2) hot rolling to rod without intermediate cooling, (3) quenching the hot rolled rod, (4) cold deforming the quenched rod and (5) subjecting the cold deformed rod to artificial aging.
Patent HU-197997-B (HU)
Inventor: KISS BELA
IPC: B67B3/00
Filed: 1985-10-03
Abstract: A találmány tárgya ismételten felhasználható zárókupak peremes szájú palackok lezárására, amelynek használati helyzetben a palack (30) száját (33) lefedő zárólapja és a száj peremét (32) körülfogó, a peremen a palack nyakrésze (31) irányában túlnyúló hengeres övrésze van, és az övrész zárási helyzetben a peremnek (32) a palack nyakrésze (31) felőli oldalához illeszkedő vállal (11) van ellátva. A találmány értelmében az övrész külső menettel rendelkező, a palack nyakrészére (31) ráhúzható, egy helyen sugárirányban felhasított nyakgyűrűből, valamint zárási helyzetben a nyakgyűrű külső mj> netébe illeszkedő belső menettel ellátott, a zí~ rólappal egybefüggő zárógyűrűből (21) áll, és a vállat (11) a nyakgyűrűnek a perem (32) felőli homlokoldala képezi.  21 3. ábra
Patent HU-197763-B (HU)
Title: Electric insulating material composition based on silicone rubber
Inventor: BOGNAR ALAJOS
IPC: C08L83/00
Filed: 1983-11-14
Abstract: Electric insulating materials contain electron capturing substance and/or a void filling voltage stabiliser made up at least partly from silicone oil contg. phenyl side gps.
Patent HU-204392-B (HU)
Title: Plant-protecting suspoemulsions
Inventor: ALBRECHT KONRAD
IPC: A01N25/04
Filed: 1987-09-16
Abstract: Plant protection agents containing one or more agents, based on suspoemulsions containing aqueous and organic phases, the organic phase containing one or more surfactants from the group of ethylene oxide/propylene oxide block polymers having an average molecular weight of 1000 - 20000. The suspoemulsions are exposed to high shear forces. Even afterwards, they exhibit constant viscosity behaviour, despite a larger drop number and smaller drop size.
Patent HU-200588-B (HU)
Inventor: ANTHONY VIVIENNE MARGARET
IPC: C07C69/734
Filed: 1985-10-16
Abstract: Die Erfindung betrifft als Fungizide nuetzliche Derivate von Acrylsaeure und Verfahren zu deren Herstellung. Mit der Erfindung werden Fungizide bereitgestellt, die in das Pflanzengewebe eindringen und sie koennen so fluechtig sein, dass sie in der Dampfphase gegen auf den Pflanzen befindliche Pilze wirksam sind. Sie koennen sowohl in der Landwirtschaft als auch in der Industrie eingesetzt werden. Die Aufgabe der Erfindung besteht darin, als Fungizide nuetzliche Verbindungen und deren Herstellungsverfahren zur Verfuegung zu stellen, die vielseitig einsetzbar sind. Die erfindungsgemaessen Verbindungen besitzen die allgemeine Formel und Stereoisomere davon, worin X, Y und Z, die gleich oder unterschiedlich sein koennen, Wasserstoff- oder Halogenatome, oder wahlweise substituierte Alkyl-, wahlweise substituierte Alkenyl-, wahlweise substituierte Aryl-, wahlweise substituierte Alkynyl-, Halogenalkyl-, Alkoxy-, Halogenalkoxy-, wahlweise substituierte Aryloxy-, wahlweise substituierte Arylalkoxy-, wahlweise substituierte Acyloxy, wahlweise substituierte Amino-, wahlweise substituierte Arylazo-, Acylamino-, Nitro-, Nitril-, CO2R3-, CONR4R5-, COR6-, CR7NR8- oder NCR9R10-Gruppen sind; oder sich die Gruppen X und Y, wenn sie sich in benachbarten Stellungen am Phenylring befinden, zur Bildung eines kondensierten Ringes vereinigen koennen, der entweder aromatisch oder aliphatisch ist und wahlweise ein oder mehrere Heteroatome enthaelt; und R1, R2, R3, R4, R5, R6, R7, R8, R9 und R10, die gleich oder unterschiedlich sein koennen, Wasserstoffatome oder Alkyl-, Cycloalkyl-, Alkenyl-, Alkynyl-, wahlweise substituierte Aryl-, wahlweise substituierte Aralkyl- oder Cycloalkylalkylgruppen sind; und Metallkomplexe davon. Formel
Patent HU-203832-B (HU)
Title: Compositions for controlling growth of plants contining azolyl-methyl-oxiranes as acitve components
Inventor: KARBACH STEFAN
IPC: A01N43/653
Filed: 1988-11-04
Abstract: Method of influencing plant growth, characterised in that the soil, the seed and/or the plants are treated with an azolyl methyl oxirane of the formula <IMAGE>  in which the substituents A and B represent C1-C4-alkyl, phenyl, naphthyl, diphenyl or phenyl which is substituted by one to three radicals from amongst the group comprising halogen, C1-C4-alkyl, C1-C4-alkoxy, C1-C4-haloalkyl, nitro or phenoxy and  Z represents the CH group or nitrogen, or their metal salts or acid addition salts, and compositions for influencing plant growth which contain at least one azolyl methyl oxirane.
Patent IT-1198787-B (IT)
Title: Meso-di:mercapto-succinic acid salts with organic bases
Inventor: CERCHIAI PIERO
IPC: C07G/
Filed: 1984-02-15
Granted: 1988-12-21
Abstract: The method obtains photographic images of selected areas or portions of Human Bodies, Animals, Fish, Birds, Insects Trees, Bushes, Flowers, Plants or Seeds and Psychic phenonema. An electro magnetic field is formed on which is carried the energy pattern of the area to be photographed on a film or photographic paper situated between the Positive and Negative conductor plates of the circuit. Changes in the electromotive force in the circuit are produced by an Infra red sensor exposed to the influence of the radiant energy emitted from the donor Body, via the introduction of the sample taken from the donor Body introduced to the Infra red sensor. The device can be battery or mains powered.
Patent IT-1238673-B (IT)
Title: New fluoro-naphthacene-di:one(s) and glycosylated derivatives
Inventor: GIOLITTI ALESSANDRO
IPC: A61K/
Filed: 1990-03-30
Granted: 1993-09-01
Abstract: (A) new 7-substd. fluoro-2beta-acetyl-2alpha,4 alpha, 5,12--tetrahydroxy-1,2,3,4-tetrahydro-6,11- naphthacenediones of formula (I) where X = H or OH; R and R1 are not the same and are H or F; R2 = H, OH or alkoxy); (B) the use of (I) for obtaining new anthracyclinic derivs. for use as chemotherapeutic cpds. with partic. reference to antitumour and antiviral activity; (C) derivs. obtd. from (I) of formula (II) (R3 = a glycosidic residue); (D) naphthacenedione cpds. of formula (III)-(VIII). Pref. 36 cpds. (II) e.g. 8-fluoro-4-demethoxydaunomycin (IIa); 8-fluoro-carminomycin and 10-fluoro-doxorubicin.
Patent IT-1213841-B (IT)
Title: Table base formation
Inventor: LUCIANO CIONINI
IPC: C04B/
Filed: 1987-10-16
Granted: 1990-01-05
Abstract: The system generates a digital pixel image in a framestore memory (20) by expanding run-length encoded data stored in a command memory (22). Each pixel has a variable characteristic such as its colour, or its depth in a 3-D image. The value of the characteristic for each written pixel is determined from the run-length encoded characteristic. The value of the characteristic for each pixel in the run is determined from a reference parameter which determines the initial value of the characteristic, and a difference parameter which represents the change in the value along the length of the run. The coordinates of the pixel runs may be determined from the coordinates of a preceding run. The initial location and run length for each run are determined relative to the preceding run by delta parameters associated with the current run. The system generates linear colour blends and automatically depth-clips images being written into the framestore (20).
Patent IT-1236590-B (IT)
Title: Gasifier for internal combustion engines (petrol) capable of transforming combustible liquids into vapours
Inventor: IGNESTI ENRICO
IPC: F02M/
Filed: 1989-12-27
Granted: 1993-03-18
Abstract: The invention has as object a gasifier for Otto cycle internal combustion engines using petrol, capable of transforming relatively volatile liquids or volatile residues into combustible gas, such as petrol, recovered (cracked) naphtha, gas oil, petroleum alcohol and others.
Patent MX-169180-B (MX)
Title: Mejoras a composiciones detergentes reforzadas que contienen agentes estabilizantes
Inventor: DELVENNE JEAN-PAUL
IPC: C11D1/835
Filed: 1986-08-19
Abstract: La presente invención se refiere a mejoras a composición detergente para tratar telas la cual comprende una suspensión de partículas de sal reforzadora de detergente inorgánica insolubles en un detergente de surfactante líquido no iónico no acuoso y un compuesto de urea o un agente en contra del asentamiento de superficie activa de sal de aminacuaternaria catiónica para aumentar la estabilidad de la suspensión.
Patent MX-165260-B (MX)
Title: Procedimiento para preparar catalizadores de plata
Inventor: BECKER MITCHELL
IPC: C07B61/00
Filed: 1987-02-24
Abstract: La presente invención se refiere a un procedimiento para preparar catalizadores de plata, adecuado para oxidar etileno con oxígeno molecular a óxido de etileno, caracterizado porque comprende a) mezclar por lo menos una cantidad estequiométrica de un compuesto de plata con una cantidad unitaria de un neoácido que tiene 7 o más átomos de carbono, en por lo menos suficiente solvente para disolver, la sal de plata que se va a formar b) hacer reaccionar la mezcla de (a) a la temperatura de ebullición de la mezcla bajo presión en la escala de 0.01 A 0-08 barias durante un tiempo suficiente para que reaccione por lo menos el 90 por ciento del neoácido con el compuesto de plata: c) impregnar un soporte poroso que tiene un área de superficie de aproximadamente 0.2 a 1.5 m cuadrado/g, con una mezcla reaccionada de (b); y d) activar el soporte impregnado de (c), calentado durante un tiempo suficiente para producir un catalizador activo para óxido de etileno.
Patent NO-149034-B (NO)
Title: Analogifremgangsmaate til fremstilling av terapeutisk virksomme n-alkylerte aminoalkoholer
Inventor: OSTERMAYER FRANZ
IPC: A61K31/38
Filed: 1979-06-01
Abstract: Analogifremgangsmåte til fremstilling av terapeutisk virksomme N-alkylerte aminoalkoholer.
Patent NO-148909-B (NO)
Inventor: WARNCKE ERNST
IPC: A62B18/04
Filed: 1980-11-03
Abstract: 1. Escape filtering apparatus having : a protective hood (1) ; an internal half-mask (4), a face abutting portion of which is provided with a cutaway region (11) ; a respiratory filter (6), which is arranged externally of the hood in a receiving portion (5) which extends through material forming the protective hood (1) ; and a banded structure (8), which can be put on by means of lugs ; characterized in that the cutaway region (11) is bordered by a lip which forms a surface (10) for abutting the face of a wearer, in that the lip edge, which defines the cutaway region (11), is urged towards a wall of the mask and in that the mask wall, the lip and a support are constructed with a substantially triangularly-shaped cross-section and form a supporting section (13) which tapers off into a flap (15) which lies alongside the bridge of the nose.
Patent NO-165983-B (NO)
Inventor: MACHATE RAINER
IPC: A47C3/025
Filed: 1986-05-22
Abstract: A chair having a seat member rotatably supported about a swivel point in the region of its front edge relative to a seat carrier. The chair also has a back member connected to at least one lever which is pivotally supported on the seat carrier. The lever is connected so that in the case of an inclination of the back member there simultaneously occurs in a predetermined relationship an inclination of the seat member so that the area of the seat back in the region of the user's lumbar vertebra is changed in such a way that the support is at an optimum during each inclined position of the seat back. A control member is hingedly connected at one end to the back member below the point of its engagement with the lever. The control member is hingedly connected to the seat carrier or to the seat at its other end in a first pivot axle spaced from a second pivot axle of the lever on the seat carrier. The lever and the control member are hingedly connected with one another by means of a connecting element, so that a relative movement between the lever and the control member in the coupling point or between the control member and its connecting point on the seat carrier or on the seat can occur.
Patent NO-173169-B (NO)
Inventor: SHIBA KENZOU
IPC: A63B21/00
Filed: 1988-12-28
Abstract: A roller 26 for applying a load to a tire 44 of a rear wheel as a drive wheel is rotatably supported by support frames 30 through a roller shaft 24. The support frames 30 are rotatable about a fixing shaft 28 penetrating their ends. A support portion 29 supporting the fixing shaft 28 is fixed to a load applying device stand 2 to be inserted in a rear frame 22. A coil spring 34 is provided between a fixing plate 32 fixed to the load applying device stand 2 and a transverse plate 31 of the support frames 30. A pedal clamp 38 to be engaged with the plate 31 in a state of the coil spring 34 being compressed is rotatably provided on the load applying device stand 2. When a load applying device is to be used, the position of the load applying device stand 2 is adjusted so that the roller 26 slightly contacts the rear wheel tire 44 with the pedal clamp 38 being engaged with the plate 31. Then, the pedal clamp 38 is disengaged therefrom and the roller 26 applies a predetermined contact force as a load to the rear wheel tire 44.
Patent NO-174011-B (NO)
Inventor: PAAVOLA JYRKI
IPC: D21B1/34
Filed: 1989-02-09
Abstract: Device to disintegrate paper, cardboard and similar materials, which device consists of a tub (1) into which the material to be disintegrated is fed and from which it is removed in the disintegrated state, and of at least one rotating rotor (3) with several blades (2, 5), situated on one of the walls of the tub (1). Current pulpers work effectively only with a mild consistency. When the consistency increases the disintegrating power decreases essentially. With the invention the problem has been solved by that at least one of the blades is a pumping blade (2) and at least one a disintegrating blade (5).
Patent NO-179056-B (NO)
Inventor: NILSSON PEKKA WALDEMAR
IPC: G05D23/13
Filed: 1989-08-29
Abstract: An electrically controlled mixing cock, comprising two electric motors (11, 12), one of which (11) adjusts the amount of water and the other one (12) adjusts the mixing ratio of cold and hot water. The mixing unit (7) of the cock and its motors (11, 12) are disposed on the fixing level (5) of the cock, appropriately below the sink unit top and a magnetic valve (17) is also provided here for guiding water to the service pipe (18) of a washing-machine. Control members (3, 5) controlling the electric motors (11, 12) and the magnetic valve (17) are provided in the cock body (1) above the fixing level. This cock is most suitable as a kitchen tap.
Patent YU-47369-B (YU)
Title: Postupak za optičko razdvajanje 3r-(3-karboksibenzil)-6-(5-fluoro-2-benzotiazolil)m etoksi-4r-hromanola
Inventor: FRIEDMAN R C
IPC: C07B57/00
Filed: 1990-08-06
Abstract: POSTUPAK ZA OPTIČKO RAZDVAJANJE 3R-(3-KARBOKSIBENZIL)-6-(5-FLUORO-2-BENZOTIAZOLIL)M ETOKSI-4R-HROMANOLA formule: ili njegove farmaceutski prihvatljive soli, naznačen time, što obuhvata sledeće faze: kombinovanje racemskog cis-3-(3-karbok-sibenzil)-6-(5-fluoro-2-benzotiazolil)metoksi-4-hromanola sa najmanje pola molarne količine kinina u metanolu na temperaturi u opsegu od oko 20 stepeni Celzijusa do oko 65 stepeni Celzijusa, pri takvoj koncentraciji da kininska so jedinjenja formule (I) kristališe suštinski nekontaminirana kininskom soli enatiomera jedinjenja formule (I); konvencionalno regenerisanje navedene kininske soli jedinjenja formule (I) i konvencionalno zakišeljavanje navedene kininske soli sa kiselinom u reakciono-inertnom rastvaraču da bi se dobilo jedinjenje formule (I). Prijava sadrži 1 nezavisni i 3 zavisna zahteva.
Patent YU-46243-B (YU)
Inventor: AUSTIN R G
IPC: C08F132/06
Filed: 1987-12-17
Abstract: Ethylene/1,5-hexadiene copolymers and higher interpolymers having structural characteristics that provide improved physical properties and processability. The ethylene polymers of the invention have narrow molecular weight distribution and/or narrow composition distribution and/or a low cluster index. The 1,5-hexadiene comonomer is predominantly incorporated as a cyclic ring in the polyethylene backbone but may also form long chain branching and intermolecular coupling without crosslinking to a gel.
Patent ZA-834135-B (ZA)
Title: Halogenophenyl glyceride esters
Inventor: ARNOULD JEAN CLAUDE
IPC: C07C69/44
Filed: 1983-06-07
Abstract: The invention concerns novel glyceride esters of anti-bacterial halogenated phenols having the formula I in which Ra and Rb are independently (3-20C)alkyl or (3-20C)alkenyl; Rc and Rd are independently chloro or bromo; Re is hydrogen, chloro or bromo; and A is (1-6C)alkylene optionally bearing one or two (1-4C)alkyl substituents. The esters are of use in the prophylaxis and/or therapy of acne vulgaris. Pharmaceutical compositions for topical administration and processes for the manufacture of the esters are also provided.